Essentially, a theory is an abstract, symbolic representation of what is conceived to be reality.

Theory is essentially an abstract and symbolic expression of reality as conceived by people.

Grammar notes: The backbone of this sentence is "A theory is an abstract, symbolic representation." A noun clause introduced by what serves as the object of of.

Thanks to modern irrigation, crops now grow abundantly in areas where once nothing but cacti and sagebrush could live.

Thanks to modern irrigation facilities, crops now thrive where only cacti and shrubs could survive.

Grammar notes: The backbone of this sentence is "Thanks to modern irrigation, crops now grow abundantly." The attributive clause introduced by where in the sentence modifies the preceding areas.

Anthropologists have discovered that fear, happiness, sadness, and surprise are universally reflected in facial expressions.

Anthropologists have discovered that fear, happiness, sadness, and surprise are reflected in facial expressions that are common to all humans.

Grammar Notes: The stem of this sentence is "Anthropologists have discovered that...". In the sentence, that introduces an object clause whose subject is "fear, happiness, sadness, and surprise".

Of the millions who saw Haley’s Comet in 1986, how many people will live long enough to see it return in the twenty-first century.

Of the millions of people who saw Halley's Comet in 1986, how many will live long enough to see it return in the 21st century?

Grammar notes: The backbone of this sentence is How many people will live long enough to see it return in the twenty-first century. This sentence looks like an ordinary question, but it actually functions as an exclamation.

The greater the population there is in a locality, the greater the need there is for water, transportation, and disposal of refuse.

The more people a place has, the greater its needs for water, transportation and waste disposal.

Grammar notes: This is a sentence pattern of "the more..., the more", which means "the more..., the more...", it is a compound sentence.

Perfectly matched pearls, strung into a necklace, bring a far higher price than the same pearls sold individually.

Perfectly matched pearls strung together into a necklace can fetch much more than if they were sold individually.

Grammar notes: The backbone of this sentence is Perfectly matched pearls bring a far higher price. The past participle matched means passive, and is used as a preposition to modify pearls; strung into a necklace is a past participle phrase used as a postposition; a far higher price than is a comparative structure, and the object of comparison is "perfectly matched pearls, strung into a necklace" and the same pearls sold individually.

The development of mechanical timepieces spurred the search for more accurate sundials with which to regulate them.

The development of mechanical timepieces led to the search for more accurate sundials with which to calibrate mechanical timepieces.

Grammar notes: The backbone of this sentence is The development of mechanical timepieces spurred the search for sundials. The which in the sentence refers to sundials.

Studies of the gravity field of the Earth indicate that its crust and mantle yield when unusual weight is placed on them.

Studies of Earth's gravity field show that the Earth's crust and mantle can deform when unusual gravity is exerted on it.

Grammar Notes: The backbone of this sentence is "Studies indicate that ...". that introduces an object clause whose backbone is its crust and mantle yield. The following when introduces an adverbial clause and serves as the time adverbial of the object clause.

Quails typically have short rounded wings that enable them to spring into full flight instantly when disturbed in their hiding places.

Quail typically have short, rounded wings, a feature that allows them to instantly take off and fly away from their hiding places when disturbed.

Grammar Notes: The stem of this sentence is Quails typically have short rounded wings. In the sentence, that introduces an attributive clause and modifies wings. This attributive clause also contains a time adverbial clause introduced by when.

Fungi are important in the process of decay, which returns ingredients to the soil, enhances soil fertility, and decomposes animal debris.

Fungi are important in the decomposition process, which returns various components to the soil, increasing its fertility and breaking down animal remains.

Grammar notes: The backbone of this sentence is Fungi are important. The attributive clause introduced by which is used to modify the process of decay. There are three coordinating predicates in this attributive clause: returns, enhancements and decomposes.

Most substance contract when they freeze so that the density of a substance’s solid is higher than the density of its liquid.

Most substances shrink when they freeze, so their density is higher in the solid state than in the liquid state.

Grammar notes: The backbone of the sentence is Most substance contract, and the when clause in the sentence serves as its time adverbial. so that is the result adverbial clause that introduces the entire sentence.

By the middle of the twentieth century, painters and sculptors in the United States had begun to exert a great worldwide influence over art.

By the mid-20th century, painters and sculptors in the United States began to have a major impact on art around the world.

Grammar notes: The backbone of this sentence is Painters and sculptors had begun to exert influence over art. The "by the middle of the twentieth century" at the beginning of the sentence is the time adverbial of the entire sentence.

Although apparently rigid, bones exhibit a degree of elasticity that enables the skeleton to withstand considerable impact.

Although bone appears to be hard, it also exhibits a certain degree of elasticity, allowing the bone to withstand larger impacts.

Grammar notes: The backbone of this sentence is Bones exhibit a degree of elasticity. The "that" in the sentence introduces the attributive clause and modifies the preceding elasticity. The "although apparently rigid" at the beginning of the sentence serves as the concession adverbial of the entire sentence.

Finally, the coughing reflex in reaction to irritants in the airway produces not a cough during sleep but a cessation of breathing.

Finally, in response to irritants in the respiratory tract, the cough reflex causes not coughing during sleep but respiratory arrest.

Grammar notes: The backbone of this sentence is The reflex produces not a cough but a cessation. The "not ... but ..." sentence pattern emphasizes the part after but; the prepositional phrase in reaction to irritants in the airway serves as an attributive, modifying the preceding the coughing reflex, in which reaction to sb./sth. is a fixed collocation , meaning "reaction or response to someone or something".

But when consumers do not know they are being lobbied, they may accept claims they would otherwise be suspicious of.

But when consumers don't know they're being persuaded, they may accept claims they would otherwise be skeptical of.

Grammar notes: The backbone of this sentence is They may accept claims. In the sentence, when introduces a time adverbial clause, in which they are being lobbied is an object clause that omits that and serves as the object of the verb know. They would otherwise be suspicious of at the end of the sentence is an attributive clause that omits that, and this attributive clause modifies claims.

Buyers and sellers should be aware of new developments in technology which can and does affect marketing activities.

Buyers and sellers alike should be aware of new developments in technology that can and do impact marketing campaigns.

Grammar notes: The backbone of this sentence is that Buyers and sellers should be aware of new developments in technology. The attributive clause introduced by which in the sentence modifies technology.

With modern offices becoming more mechanized, designers are attempting to personalize them with warmer, less severe interiors.

As modern offices become increasingly dull, designers are trying to personalize offices with interiors that are warmer and less austere.

Grammar notes: The backbone of this sentence is that Designers are attempting to personalize them. The beginning of the sentence is the accompanying state of with.

The worker and soldier castes of termites consist of both males and females, and the queen lives permanently with a male consort.

The worker and soldier castes in termites are composed of males and females, and the queen lives permanently with a male mate.

Grammar notes: This sentence is composed of two parallel sentences connected by and. The stem of the first clause is the castes consist of both males and females; the stem of the second clause is the queen lives with a consort.

Children with parents whose guidance is firm, consistent, and rational are inclined to possess high levels of self-confidence.

Children whose parents' teachings are firm, consistent, and rational tend to have a high degree of self-confidence.

Grammar notes: The backbone of this sentence is Children are inclined to possess high levels of self-confidence. The attributive clause introduced by whose modifies parents.

Lucretia Mott’s influence was so significant that she has been credited by some authorities as the originator of feminism in the United States.

Lucretia Matt's influence was so great that some authorities identified her as the founder of the American feminist movement.

Grammar notes: The backbone of this sentence is “Lucretia Mott’s influence was so significant that ...”. "so... that..." means "so... that...", and that introduces a resultant adverbial clause.

No social crusade aroused Elizabeth Williams’ enthusiasm more than the expansion of educational facilities for immigrants to the United States.

No social movement inspired Elizabeth Williams more than the expansion of educational facilities for immigrants in the United States.

Grammar notes: The backbone of this sentence is “No social crusade aroused Elizabeth Williams’ enthusiasm more than the expansion of educational facilities.”

Since wind-pollinated flowers have no need to attract insects or other animals, they have dispensed with bright petals, nectar, and scent.

Because wind-pollinated flowers don't need to attract insects or other animals, they no longer need brightly colored petals, nectar and scent.

Grammar notes: The backbone of this sentence is "They have dispensed with petals, nectar, and scent", where "dispense with" is a fixed collocation, meaning "no longer needed". Since at the beginning of the sentence introduces an adverbial clause of reason.

In the absence of a tradition of classical stone-carving and building, the desire to develop Roman amenities would have been difficult to fulfill.

The desire to develop Roman-style amenities would have been difficult to realize due to the lack of classical stone carving and architectural traditions.

Grammar notes: The backbone of this sentence is The desire to develop Roman amenities would have been difficult to fulfill. The "in the absence ... building" at the beginning of the sentence is a prepositional phrase used as an adverbial. Would have been is a subjunctive mood, indicating the opposite of past facts.

Out in remote areas of the countryside, in rural locations, music was more traditional; the same songs were enjoyed by previous generations.

In remote and remote villages, in rural areas, the music is more traditional; the same songs are listened to by generations.

Grammar notes: The backbone of this sentence is "Music was more traditional; the same songs were enjoyed." The beginning of the sentence "out in remote ... rural locations" is an adverbial of location.

In the second half of the millennium, in the south around the city of Uruk, there was an enormous escalation in the area occupied by permanent settlements.

During the second half of the millennium, the area occupied by permanent settlements south of the city of Uruk increased significantly.

Grammar Notes: The stem of the sentence is There was an escalation. The past participle phrase occupied by permanent settlements is used as a postpositional attributive to modify the area. The two phrases starting with in at the beginning of the sentence serve as the adverbials of time and place respectively.

By fossils, we mean traces of prehistoric animals such as bones, which become mineralized, or impressions of bones or organs that are left in stone.

When we talk about fossils, we mean the remains of prehistoric creatures, such as bones that have been mineralized, or impressions of bones or organs left on stone.

Grammar notes: The stem of this sentence is "By fossils, we mean traces of prehistoric animals." In the sentence, such as is followed by two parallel elements connected by or, namely bones and impressions of bones or organs. These two parallel elements are each followed by an attributive clause. Among them, bones are followed by a non-restrictive attributive clause introduced by which, and impressions of bones or organs are followed by an attributive clause introduced by that.

The application of electronic controls made possible by the microprocessor and computer storage have multiplied the uses of the modern typewriter.

Microprocessors and computer memory made possible the use of electronic controls that exponentially increased the capabilities of modern typewriters.

Grammar notes: The backbone of this sentence is The application of electronic controls have multiplied the uses of the modern typewriter. The past participle phrase made possible by the microprocessor and computer storage is used as a postpositional attributive modification of electronic controls.

Even though the precise qualities of hero in literary words may vary over time, the basic exemplary function of the hero seems to remain constant.

Even if the exact qualities of heroes described in literary language change over time, the hero's basic role as exemplar seems to remain the same.

Grammar Notes: The backbone of this sentence is The function of the hero seems to remain constant. In the sentence, even though guides the concession adverbial clause.

When Henry Ford first sought financial backing for making cars, the very notion of farmers and clerks owning automobiles was considered ridiculous.

When Henry Ford first sought funding to build automobiles, the idea that farmers and office workers could own automobiles seemed ludicrous.

Grammar notes: The backbone of this sentence is The notion was considered ridiculous. In the sentence, when introduces the time adverbial clause; the present participle phrase owning automobiles is used as a postpositional attributive modification of farmers and clerks.

Many people who wanted to become archaeologists ended up pursuing other careers and contributing to archaeological research only as unpaid amateurs.

Many would-be archaeologists end up pursuing other careers, contributing only to archaeological research as unpaid amateurs.

Grammar notes: The backbone of this sentence is Many people ended up pursuing other careers and contributing to archaeological research. In the sentence, who introduces the attributive clause who wanted to become archaeologists and modifies people; and connects two parallel non-predicate verb forms, pursuing and contributing.

Even before the discovery of germs, beliefs that disease spread by “miasmas” (noxious forms of bad air) prompted attention to sewers and open garbage.

Even before the discovery of bacteria, the idea that disease was spread through "miasmas" (poisonous malignant gases) fueled concern about drains and open garbage.

Grammar notes: The backbone of this sentence is Beliefs prompted attention. The prepositional phrase "even before the discovery of germs" at the beginning of the sentence serves as a time adverbial, and the "that" after "beliefs" guides the appositive clause to explain "beliefs".

Since the consumer considers the best fruit to be that which is the most attractive, the grower must provide products that satisfy the discerning eye.

Because customers consider the best fruit to be the most attractive looking, growers must provide products that satisfy their customers' discerning tastes.

Grammar notes: The backbone of this sentence is The grower must provide products. The beginning of the sentence is the adverbial clause of reason introduced by since. The backbone of this clause is The consumer considers the best fruit to be that, where that is a pronoun, referring to fruit, and the following which is the most attractive is an attributive clause, modifying the previous pronoun that , indicating what the fruit should look like. That satisfy the discerning eye in the main sentence is an attributive clause that modifies products.

With no oceans to dissolve it, outgassed carbon dioxide began to accumulate in the atmosphere, intensifying the greenhouse effect even more.

Without oceans to dissolve carbon dioxide, the emitted carbon dioxide begins to accumulate in the atmosphere, further exacerbating the greenhouse effect.

Grammar notes: The backbone of this sentence is Carbon dioxide began to accumulate in the atmosphere. The beginning of the sentence is an independent nominative structure introduced by with. At the end of the sentence, intensifying the greenhouse effect even more is a present participle phrase used as the result adverbial.

Buildings contribute to human life when they provide shelter, enrich space, complement their site, suit the climate, and are economically feasible.

Buildings contribute a lot to human life. They provide shelter, enrich space, complete people's homes, adapt to climate, and make them economically affordable.

Grammar notes: The backbone of this sentence is "Buildings contribute to life when they...". The adverbial clause introduced by when contains five predicate verbs: provide, enrich, complement, suit, and are.

Research into the dynamics of storms is directed toward improving the ability to predict these events and thus to minimize damage and avoid loss of life

Research into storm dynamics aims to improve the ability to predict such storm events, thereby reducing damage and avoiding casualties.

Grammar notes: The backbone of this sentence is Research is directed toward improving the ability. The infinitive after ability "to predict ... and thus to minimize ... and avoid ..." is used as the postpositional attributive of ability.

Their streamlined bodies, the absence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land dwelling mammals

Their streamlined bodies, the disappearance of hind legs, and the appearance of tail blades and spiracles cannot hide their similarities to terrestrial mammals.

Grammar notes: The backbone of this sentence is "Their bodies, the absence of ..., and the presence of ... cannot disguise their affinities with ...". The subject of the sentence is longer and consists of three noun phrases.

Scientists do not know why dinosaurs became extinct, but some theories postulate that changes in geography, climate, and sea levels were responsible.

Scientists don't know why the dinosaurs became extinct, but some theories theorize it was due to changes in geography, climate and sea levels.

Grammar notes: In this sentence, but connects two parallel clauses. The first clause contains an object clause introduced by why, and the backbone of the first clause is "scientists do not know why..."; the second clause contains an object clause introduced by that, and the second clause The backbone of is "theories postulate that...".

The elimination of inflation would ensure that the amount of money used in repaying a loan would have the same value as the amount of money borrowed.

Eliminating inflation ensures that the money used to repay the loan is worth the same as the money borrowed.

Grammar notes: The backbone of this sentence is "The elimination of inflation would ensure that ...", where that introduces an object clause.

Futurism, an early twentieth-century movement in art, rejected all traditions and attempted to glorify contemporary life by emphasizing the machine and motion.

Futurism was an artistic trend in the early 20th century that abandoned all traditions and tried to beautify contemporary life by emphasizing machinery and movement.

Grammar notes: The backbone of this sentence is Futurism rejected all traditions and attempted to glorify contemporary life. The sentence "an early twentieth-century movement in art" is a parenthesis, supplementary explanation of futurism.

Acids are chemical compounds that, in water solution, have a sharp taste, a corrosive action on metals, and the ability to turn certain blue vegetable dyes red.

Acids are compounds that, when dissolved in water, have a strong odor, are corrosive to metals, and can turn some blue plant dyes red.

Grammar Notes: The backbone of this sentence is Acids are chemical compounds. The following that introduces an attributive clause modifying compounds.

In other instances, such as the Indus River Valley, the cities lacked a royal precinct and the ostenatious palaces that marked their contemporaries elsewhere.

But in other cases, such as in the Indus Valley, cities did not have the iconic royal quarters and ostentatious palaces that characterized other places of the period.

Grammar notes: The stem of this sentence is The cities lacked a precinct and the palaces. The attributive clause introduced by that in the sentence modifies the ostenatious palaces.

Offshore drilling platforms extend the search for oil to the ocean’s continental fixtures—those gently sloping submarine regions at the edges of the continents.

Offshore drilling platforms extend the search for oil onto the ocean's continental shelf—the gentle slope beneath the shallow sea near land.

Grammar notes: The backbone of this sentence is Platforms extend the search to the continental shelves. The noun phrase after the dash “those gently sloping ... continents” explains the ocean’s continental shelves.

Even those artists who were most dependent on photography became reluctant to admit that they made use of it, in case this compromised their professional standing.

Even those artists who relied most heavily on photography became reluctant to admit that they used it, lest it affect their professional status.

Grammar notes: The backbone of this sentence is "Those artists became reluctant to...", in which who introduces an attributive clause modifying artists. The "that" after admit introduces an object clause. The adverbial clause of purpose introduced by in case serves as the adverbial of the entire sentence.

According to anthropologists, the earliest ancestors of humans that stood upright resembled chimpanzees facially, with sloping foreheads and protruding brows.

According to anthropologists, the earliest human ancestors who walked upright had facial profiles similar to those of chimpanzees, with sloping foreheads and prominent eyebrows.

Grammar Notes: The stem of this sentence is The ancestors resembled chimpanzees. The attributive clause that stood upright modifies humans; in the prepositional phrase with sloping foreheads and protruding brows, the present participles sloping and protruding serve as prepositional attributives to modify foreheads and brows respectively, and the entire prepositional phrase serves as the accompanying adverbial in the clause.

Anarchism is a term describing a cluster of doctrines and attitudes whose principal uniting feature is the belief that government is both harmful and unnecessary.

The term anarchism describes a group of doctrines and attitudes whose main common characteristic is the belief that government is harmful and unnecessary.

Grammar notes: The backbone of this sentence is Anarchism is a term. The present participle phrase "describing a cluster ... unnecessary" serves as a postpositional attributive modification of a term, in which "who" introduces an attributive clause to modify a cluster of doctrines and attitudes. The attributive clause also contains an appositive clause introduced by that to explain the belief.

A rotary engine attached to the steam engine enabled shafts to be turned and machines to be driven, resulting in mills using steam power to spin and weave cotton.

A rotary engine connected to the steam engine rotated bearings to drive the machine, and as a result, factories using steam power to spin cotton cloth emerged.

Grammar notes: The backbone of this sentence is A rotary engine enabled shafts to be turned and machines to be driven. In the sentence, attached to the steam engine is a past participle phrase used as a postpositional attributive modification of a rotary engine. The second half of the sentence, "resulting in mills using steam power to spin and weave cotton", is a present participle phrase used as a result adverbial at the end of the sentence, which also contains a present participle phrase "using steam power to spin and weave cotton" used as a postpositional attributive to modify mills.

Self-awareness, even in its earliest stages, might entail an awareness of others, the ability to see their perspective and to look at the world from another’s point of view.

Self-awareness, even in its earliest stages, may involve awareness of other people, the ability to understand other people's perspectives and to see the world from their perspective.

Grammar notes: The backbone of this sentence is that self-awareness might entail an awareness of others. The noun phrase “the ability to see ... point of view” is used as an appositive to explain the preceding awareness of others; where and connects the parallel infinitives to see their perspective and to look at the world from another’s point of view.

Various committees acted as an executive branch, implementing policies of the assembly and supervising, for instance, the food and water supplies and public buildings.

The committees act as an executive branch to implement parliamentary policy and oversee matters such as food and water supplies and public buildings.

Grammar notes: The stem of this sentence is Various committees acted as an executive branch. The following implementing policies of the assembly and supervising the food and water supplies and public buildings are two parallel present participle phrases connected by and. They serve as accompanying adverbials in the sentence, indicating that the predicate and the predicate acted as an executive branch occur at the same time.

A mountain range may emerge and gradually split a population of organisms that can inhabit only lowland lakes; certain fish populations might become isolated in this way.

A mountain range may appear and gradually isolate a population of organisms that only inhabit lowland lakes, and certain fish stocks may be isolated in this way.

Grammar Notes: This sentence is two parallel clauses connected by a semicolon. The backbone of the first clause is A mountain range may emerge and split a population, and the attributive clause that can inhabit only lowland lakes modifies organisms; the backbone of the second clause is Populations might become isolated.

Think of it this way, humans originally needed to have a stronger sensitivity to bitter-tasting foods so they could learn what plants were good for them and which ones might be poisonous.

Think of it this way, humans initially needed to be more sensitive to bitter foods so they could know which plants were good for them and which plants might be poisonous.

Grammar notes: The backbone of this sentence is Humans needed to have a sensitivity. Sensitivity is a fixed collocation with the following preposition to; so is used as a conjunction to guide the adverbial clause of purpose. What plants were good for them and which ones might be poisonous are juxtaposed by and, and together they are the object of the verb learn.

Because eastern plows could not penetrate the densely tangled roots of prairie grass, the earliest settlers erected farms along the boundary separating the forest from the prairie.

Because Eastern plows could not penetrate the roots of the dense, tangled grasses of the prairie, early settlers established farms along the dividing line between forest and prairie.

Grammar notes: The stem of this sentence is The settlers erected farms. Because at the beginning of the sentence introduces the adverbial clause of reason. The present participle phrase separating the forest from the prairie is used as a postpositional attributive to modify the boundary.

If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun’s rate of movement across the sky.

If the artificial sun remained stationary, the birds would change their orientation relative to the sun at a rate of 15 degrees per hour, which is exactly how fast the sun travels across the sky.

Grammar notes: The backbone of this sentence is The birds would shift direction. The beginning of the sentence is a conditional adverbial clause introduced by if, and the noun phrase the Sun’s rate of movement across the sky at the end of the sentence is an appositive, explaining the previous 15 degrees per hour.

The Industrial Revolution had several roots, one of which was a commercial revolution that, beginning as far back as the sixteenth century, accompanied Europe’s expansion overseas.

The Industrial Revolution had several roots, one of which was the Commercial Revolution, which began as far back as the 16th century as Europe expanded overseas.

Grammar notes: The backbone of this sentence is The Industrial Revolution had roots. The non-restrictive attributive clause introduced by which modifies roots, and an attributive clause introduced by that is embedded in it to modify commercial revolution. The present participle phrase beginning as far back as the sixteenth century serves as the accompanying adverbial in the attributive clause introduced by that.

The jaw joints of many advanced herbivores, such as cows, lie at a different level than the tooth row, allowing transverse tearing, shredding, and compression of plant material.

In many advanced herbivores, such as cattle, the jaw joints and tooth rows are located at different levels, allowing them to laterally tear, chop, and compress plant material.

Grammar notes: The backbone of this sentence is The jaw joints lie at a different level than the tooth row. "allowing ... plant material" is a non-predicate structure used as an accompanying adverbial, in which tearing, shredding and compression are the co-ordinate objects of allowing.

So musical instruments evolved in ways that optimize their acoustical properties—how the instrument vibrates and sends those vibrations through the air to our eardrums.

So the way musical instruments have evolved is by optimizing their acoustic properties, that is, how they vibrate and carry the resulting vibrations through the air to our eardrums.

Grammar notes: The backbone of this sentence is "Musical instruments evolved in ways that...". In the sentence, the attributive clause introduced by that modifies ways, and the appositive clause introduced by how explains the acoustic properties.

German printers had the disadvantage of working with the complex typeface that the Italians sneeringly referred to as “Gothic” and that later became known as black letter.

The shortcoming of German printers was the use of a complex font that the Italians derisively called "Gothic" font, which later became known as boldface.

Grammar Notes: The stem of this sentence is "Printers had the disadvantage of...". It is followed by two attributive clauses introduced by that, "that the Italians sneeringly referred to as..." and "that later became known as...", both of which are used to modify the complex typeface.

Elizabeth Blackwell, the first woman medical doctor in the United States, founded the New York Infirmary, an institution that has always had a completely female medical staff.

Elizabeth Blackwell, the first female physician in the United States, founded the New York Clinic, which has historically had an all-female medical staff.

Grammar notes: The stem of this sentence is Elizabeth Blackwell founded the New York Infirmary. Among them, the first woman medical doctor in the United States is an appositive of Elizabeth Blackwell; "an institution that... medical staff" is an appositive of the New York Infirmary. This appositive structure is also modified by an attributive clause introduced by that. an institution.

We’ve gone over where coral reefs are usually formed—along the edges of shallow ocean banks in tropical or subtropical regions, and the fact that they are declining at an alarming rate.

We've talked about where coral reefs typically form—along the fringes of shallow coastal waters in tropical or subtropical regions—and the fact that they are disappearing at an alarming rate.

Grammar notes: The backbone of this sentence is “We’ve gone over where ... and the fact that ...”. In the sentence, "where coral reefs are usually formed" and "the fact that..." are co-ordinate components and together serve as the object of the main clause. Where guides the object clause and that guides the appositive clause of the fact. The words after the dash along the edges of shallow ocean banks in tropical or subtropical regions explain where coral reefs are usually formed.

Raised beaches often consist of areas of sand, pebbles, or dunes, sometimes containing seashells or piles of debris comprising shells and bones of marine animals used by humans.

Rise beaches usually consist of sandbars, pebbles, or dunes, sometimes containing shells or piles of debris consisting of shells and bones of marine animals used by humans.

Grammar notes: The stem of this sentence is "Raised beaches often consist of areas of sand, pebbles, or dunes." Containing is the present participle, which guides the accompanying adverbial and expresses the simultaneous progress with the predicate verb "consist of". The present participle phrase "comprising shells ... by humans" is used as a postpositional attributive to modify piles of debris.

But as more and more accumulations of strata were cataloged in more and more places, it became clear that the sequences of rocks sometimes differed from region to region and that no rock type was ever going to become a reliable time marker throughout the world.

As more and more forms of accumulation of rock formations were cataloged in more and more places, it became clear that the sequence of rock formations sometimes varied from region to region, and no specific rock formation could be recognized worldwide. It is a reliable time mark.

Grammar Notes: The stem of this sentence is "It became clear that ... and that ...". The two thats each introduce a subject clause and serve as the real subject of this sentence: that the sequences differed from region to region and that no rock type was going to become a time marker throughout the world. The as at the beginning of the sentence introduces an adverbial clause of reason.

This was an important innovation, because the camel’s ability to thrive in harsh desert conditions and to carry large loads cheaply made it an effective and efficient means of transportation.

This was an important innovation because camels thrived in harsh desert environments and transported large amounts of cargo cheaply, making them an effective and efficient mode of transportation.

Grammar Notes: The stem of this sentence is This was an innovation. This is followed by the adverbial clause of reason introduced by because. The backbone of the clause is The camel’s abilities made it a means of transportation. ability to do sth. is a fixed collocation, indicating the ability to do something.

These people exploited the landscape intensively, foraging on hill slopes for wild cereal grasses and nuts, while hunting gazelle and other game on grassy lowlands and in river valleys.

These people exploited the area intensively, scouring the slopes for wild grains and nuts and hunting gazelles and other game in the grassy lowlands and river valleys.

Grammar notes: The backbone of this sentence is People exploited the landscape. while connects two parallel present participle phrases "foraging... nuts" and "hunting... valleys". These two present participle phrases serve as adverbials to express accompanying states.

The recognition that many aspects of the modern flora and fauna were present on both sides of the Bering Sea as remnants of the ice-age landscape led to this region being named Beringia.

It is recognized that many features of modern flora and fauna were also present on both sides of the Bering Sea in the past as remnants of Ice Age landscapes. This realization led to the area being named Beringia.

Grammar notes: The backbone of this sentence is The recognition led to this region being named Beringia. The appositive clause "that many aspects... landscape" is used to explain the recognition. The as in the clause is used as a preposition, followed by a noun phrase.

Thus, the recalling of an event (a hunt, battle, or other feat) is elaborated through the narrator’s pantomime and impersonation and eventually through each role being assumed by a different person.

Thus, when recalling an event (a hunt, a battle, or some other feat), the narrator presented it in detail through his own gestures and imitations, which eventually evolved into different people playing different roles. .

Grammar notes: The backbone of this sentence is "Thus, the recalling is elaborated through ... and through ...". Each role being assumed by a different person is a compound structure of gerund.

The extreme seriousness of desertification results from the vast areas of land and the tremendous numbers of people affected, as well as from the great difficulty of reversing or even slowing the process.

The problem of desertification is extremely serious. This is because a vast area and a large number of people are affected by desertification. Moreover, it is difficult to reverse the process of desertification, even if it only slows down the speed of desertification.

Grammar notes: The backbone of this sentence is "The seriousness results from ... and ..., as well as from ... or ...". Results from are followed by four noun phrases, namely the vast areas of land, the tremendous numbers of people affected, the great difficulty of reversing and slowing the process, in which the great difficulty of is omitted before slowing the process.

Before starting on a sea voyage, prudent navigators learn the sea charts, study the sailing directions, and memorize lighthouse locations to prepare themselves for any conditions they might encounter.

Before setting sail, prudent sailors study charts, study headings, and memorize the locations of lighthouses so that they are prepared for any situation they may encounter.

Grammar notes: The backbone of this sentence is "Navigators learn the charts, study the directions, and memorize locations." The "before" at the beginning of the sentence is followed by the gerund form. The "to prepare...encounter" at the end of the sentence is an adverbial of purpose, and the attributive clause they might encounter modifies conditions. The relative pronoun that of the attributive clause is omitted in the clause.

The question of why infantile amnesia occurs has intrigued psychologists for decades, especially in light of ample evidence that infants and young children can display impressive memory capabilities.

The question of why forgetting occurs in infancy has interested psychologists for decades, especially given the overwhelming evidence that infants and young children can display surprising memory abilities.

Grammar Notes

The backbone of this sentence is The question has intrigued psychologists. The "that" in the sentence introduces the appositive clause "that infants... capabilities", which is used to explain evidence.

Researchers can drill core samples, uh, basically get a cross-section of a tree without having to kill it, look at the rings and get a picture of what the climate was like in the basin for each of the tree’s years.

Researchers can drill core samples, essentially taking a cross-section of a tree without killing the tree, and then look at the growth rings to learn what the climate is like in the basin where the tree is located each year.

Grammar notes: The backbone of this sentence is "Researchers can drill samples, get a cross-section, look at the rings and get a picture." The four predicate verbs of the main clause are drill, get, look at and get, which are connected in parallel by commas and and.

Great Britain’s better-developed banking and credit system also helped speed the industrial progress, as did the fact that it was the home of an impressive array of entrepreneurs and inventors.

Britain's more sophisticated banking and credit system also helped to speed up industrial progress, as did the fact that Britain had a long line of amazing entrepreneurs and inventors.

Grammar notes: The backbone of this sentence is Banking and credit system also helped speed the progress. In the sentence, as introduces an adverbial clause, which means "like...", and the clause is inverted; it also contains an appositive clause introduced by that, which is used to explain the fact.

Confronted with a multitude of unreliable figures, economists have compared the population records with the aggregate data for cultivated land area and grain production in the six centuries since 1368.

Faced with a flood of unreliable figures, economists compared population records with aggregate data on cultivated area and grain production for six centuries starting in 1368.

Grammar notes: The backbone of this sentence is economists have compared the records with the data. The beginning of the sentence is a non-predicate structure in the form of past participle, indicating passiveness, and the logical subject is economists.

Apparently, species-rich plots were likely to contain some drought-resistant plant species that grew better in drought years, compensating for the poor growth of less-tolerant species.

Clearly, species-rich plots are likely to contain some drought-tolerant plant species that grow better in drought years, compensating for the poor growth of those that are not drought-tolerant.

Grammar notes: The backbone of this sentence is Species-rich plots were likely to contain some drought-resistant plant species. The attributive clause introduced by that modifies some drought-resistant plant species. "compensating for..." in the sentence is a non-predicate structure and serves as an accompanying adverbial in the attributive clause.

Even more shocking is the fact that the number and rate of imprisonment have more than doubled over the past twenty years, and recidivism—that is the rate for re-arrest—is more than 60 percent.

Even more startling is the fact that the number and rate of incarcerations has more than doubled in the past 20 years, while the recidivism rate, or the rate of rearrests, is above 60 percent.

Grammar notes: The backbone of this sentence is Even more shocking is the fact. The predicate even more shocking in this sentence is placed at the beginning of the sentence, before the verb be, and the whole sentence is an inversion sentence. In "the fact that ... more than 60 percent", the first that introduces the appositive clause and explains the fact. The appositive clause is connected by and to two simple sentences, namely "the number and rate ... over the past twenty years” and “recidivism ... more than 60 percent.”

These plants propagate by producing spores—tiny fertilized cells that contain all the instructions for making a new plant—but the spores are unprotected by any outer coating and carry no supply of nutrient.

These plants reproduce by producing spores—tiny, fertilized cells that carry all the instructions for making a new plant—but they are not protected by any outer skin and have no nutrient supply.

Grammar notes: This is a compound sentence containing but. The backbone of the first clause is "These plants propagate by..."; the backbone of the second clause is "The spores are unprotected by... and carry no supply...". The attributive clause that contains all the instructions for making a new plant modifies tiny fertilized cells. The appositive phrase tiny fertilized cells refers to the preceding species.

Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.

At the same time, the deadliest strains of the virus died out with their hosts, as natural selection favored strains that could infect but not kill their hosts. Therefore, natural selection stabilizes the relationship between host and parasite.

Grammar notes: The stem of the first sentence is The strains perished. as introduces the adverbial clause of reason "as natural selection favored ... not kill them", which also contains an attributive clause introduced by that, modifying the previous noun strains. The backbone of the second sentence is Natural selection stabilized relationship.

The residence time is the average length of time that any particular molecule of water remains in the lake, and it is calculated by dividing the volume of water in the lake by the rate at which water leaves the lake.

Residence time refers to the average length of time a specific water molecule remains in the lake. This is calculated by dividing the volume of water in the lake by the rate at which water flows out of the lake.

Grammar notes: This is a compound sentence connected by and. The backbone of the first clause is The residence time is the average length of time, followed by that which introduces an attributive clause. The backbone of the second clause is "It is calculated by...", in which the attributive clause at which water leaves the lake modifies the previous noun the rate.

An eye is a collection of cells that are specialized for light detection through the presence of photosensitive pigment as well as a means of restricting the direction of incoming light that will strike the photosensitive cells.

The eye is made up of cells specialized in detecting light sources through the use of phytochromes, which also serve to limit the direction of incoming light hitting photoreceptor cells.

Grammar notes: The backbone of this sentence is "An eye is a collection of cells ... as well as a means ...", as well as connects the coordinating components a collection of cells and a means. The first attributive clause introduced by that, "that are specialized... pigment", modifies cells; the second attributive clause introduced by that, that will strike the photosensitive cells, modifies incoming light.

Sociologists view primary groups as bridges between individuals and the larger society because they transmit, mediate, and interpret a society’s cultural patterns and provide the sense of oneness so critical for social solidarity.

Sociologists view primary groups as bridges between individuals and larger social groups because they convey, mediate, and interpret a society's cultural patterns and provide a sense of harmony that is crucial to social cohesion.

Grammar notes: The stem of this sentence is Sociologists view primary groups as bridges. because introduces an adverbial clause of reason. The subject of the clause is they. The clause connects two parallel predicates through and, namely "transmit, mediate, and interpret a society's cultural patterns" and "provide the sense of oneness so critical for society" solidarity”.

Importing the grain, which would have been expensive and time consuming for the Dutch to have produced themselves, kept the price of grain low and thus stimulated individual demand for other foodstuffs and consumer goods.

It was expensive and time-consuming for the Dutch to produce their own food. Importing food kept the price of food at a low level, thus stimulating individual demand for other food and consumer goods.

Grammar notes: The backbone of this sentence is Importing the grain kept the price low and thus stimulated demand. which introduces a non-finite attributive clause that modifies the preceding noun the grain. The attributive clause "would have been expensive and time consuming" uses the subjunctive mood, indicating the opposite of past facts.

While the men who make faithful copies of sand paintings from the past represent the principle of stability in Navajo thought, women embody dynamism and create new designs for every weaving they make.

The men, who faithfully replicate the sand drawings of the past, represent the principle of stability in Navajo thought, while the women represent dynamism, creating new designs each time they weave.

Grammar notes: In this sentence, while is used as a coordinating conjunction, connecting two complete sentences to express the contrast between the two. The backbone of the first clause is The men represent the principle of stability; who guides the attributive clause to modify the men. The backbone of the second clause is Women embody dynamism and create designs; the relative pronoun that is omitted and the attributive clause they make modifies weaving.

In turn, a deep attachment to the land, and to the stability which rural life engenders, fostered the Roman virtues: gravitas, a sense of responsibility, pietas, a sense of devotion to family and country, and iustitia, a sense of the natural order.

In turn, a deep attachment to the land and the stability that rural life provided gave birth to the Roman character: gravitas, a sense of duty; pietas, devotion to family and country; and iustitia, a sense of natural order.

Grammar Notes: The stem of this sentence is "A deep attachment fostered the virtues: gravitas, pietas, and iustitia." Attachment to is a fixed collocation, meaning "attachment to...". In this sentence, attachment to is followed by and to connect the land and the stability in parallel. The attributive clause which rural life engenders modifies the previous stability. There are three parallel nouns after the colon: gravitas, pietas and iustitia. Each noun is followed by a noun phrase as an appositive to explain the meaning of the noun.

In contrast to mammals and birds, amphibians are unable to produce thermal energy through their metabolic activity, which would allow them to regulate their body temperature independent of the surrounding or ambient temperature.

In contrast to mammals and birds, amphibians are unable to generate heat energy through their metabolic activities, which allows them to regulate body temperature independently of the surrounding ambient temperature.

Grammar notes: The backbone of this sentence is that Amphibians are unable to produce thermal energy. The attributive clause "which would allow ... ambient temperature" modifies the previous sentence. The independent of the surrounding or ambient temperature in the attributive clause is an adjective phrase that explains how the predicate verb regulate occurs.

This is because the gaps among the original grains are often not totally plugged with cementing chemicals; also, parts of the original grains may become dissolved by percolating groundwater, either while consolidation is taking place or at any time afterwards.

This is because the gaps between the particles are usually not completely filled with cementing chemicals initially, and some of the particles are likely to be dissolved by seeping groundwater during or after curing.

Grammar Notes: The backbone of this sentence is "This is because...". The predicative clause introduced by because is the main content of this sentence, and its backbone is "the gaps are not plugged with chemicals; also, parts of... may become dissolved by groundwater, either... or...".

The growth of mutual trust among merchants facilitated the growth of sales on credit and led to new developments in finance, such as the bill of exchange, a device that made the long, slow, and very dangerous shipment of coins unnecessary.

The growth of mutual trust between merchants promoted the growth of credit sales and led to new financial developments, such as money orders, which made the long, slow, and very dangerous transportation of coins unnecessary.

Grammar notes: The backbone of this sentence is The growth of mutual trust facilitated the growth of sales on credit and led to new developments in finance. The noun phrase "a device that ... shipment of coins unnecessary" serves as the appositive of the bill of exchange and serves as an explanation. A device is followed by the attributive clause leading to that.

Widely reported, if somewhat distrusted, accounts by figures like the famous traveler from Venice, Marco Polo, the willingness of people in China to trade with Europeans and of the immensity of the wealth to be gained by such contact made the idea irresistible.

It has been widely reported, though probably unconvincing, that figures such as the famous Venetian traveler Marco Polo described the Chinese's willingness to trade with Europeans and the vast wealth that Europe could gain through such trading relationships. This made the idea of ​​direct trade between Europe and the East irresistible.

Grammar notes: The backbone of this sentence is Accounts made the idea irresistible. The past participle phrase "widely reported" at the beginning of the sentence is used as an accompanying adverbial, and it logically forms a passive relationship with the subject "accounts" of the main clause. If somewhat distrusted is an interjection, and its subject is the accounts of the main clause. The phrase accounts by sb. of sth. is a fixed collocation, meaning "a description of something made by someone". The word "and" in the sentence connects two parallel contents: "of the willingness of... Europeans" and "of the immensity of... contact".

In the wake of the Roman Empire’s conquest of Britain in the first century A.D., a large number of troops stayed in the new province, and these troops had a considerable impact on Britain with their camps, fortifications, and participation in the local economy.

After the Roman Empire conquered Britain in the 1st century AD, a large number of troops were stationed in this new province. The military camps, city defenses and their participation in the local economy of these troops had an important impact on Britain.

Grammar notes: The backbone of this sentence is "troops stayed in the province, and troops had a(n) impact on Britain." In the sentence, in the wake of sb./sth. is a fixed collocation, meaning "comes after...; follows after..."; the prepositional phrase "with their camps... economy" is used as an adverbial.

While many programs designed for preschoolers focus primarily on social and emotional factors, some are geared mainly toward promoting cognitive gains and preparing preschoolers for the formal instruction they will experience when they start kindergarten.

Many programs designed for preschoolers focus primarily on social and emotional factors, while some are primarily designed to enhance preschoolers' cognitive gains in preparation for the formal instruction they will experience after kindergarten.

Grammar notes: The backbone of this sentence is Some are geared toward promoting gains and preparing preschoolers. The while guides the adverbial clause, its backbone is programs focus on factors, and the past participle phrase designed for preschoolers modifies the noun programs. The attributive clause "they will experience ... kindergarten" modifies the formal instruction, and the relative pronoun that guides the attributive clause serves as the object in the clause, so it is omitted; the attributive clause also contains a time adverbial clause when they start kindergarten.

Hero compiled descriptions and sketches of 70 some clever little, mechanical devices, most of which utilized compressed air to cause water, or in some cases, wine to flow from one place to another, or sometimes to squirt or to make some kind of noise.

Hero compiled descriptions and sketches of some 70 ingenious little mechanical devices, most of which used compressed air to move water—or, in some cases, wine—from one place to another, or to Sometimes it sprays out or makes some noise.

Grammar notes: The backbone of this sentence is Hero compiled descriptions and sketches. The non-finite attributive clause introduced by which modifies the preceding noun phrase "70 some clever little, mechanical devices". The backbone of the attributive clause is most of which utilized compressed air, in which the past participle compressed expresses passiveness and is used as a preposition to modify air; cause sth. to do sth. is a fixed collocation, meaning "to make something do something". In the sentence Water and wine are juxtaposed by or, and to flow, to squirt and to make are also juxtaposed by or.

Introducing genetically modified trees, designed for fast growth and high yield in given geographic conditions, would satisfy the demand for wood in many of those areas and save the endangered native trees, which often include unique or rare species.

The introduction of genetically modified trees that grow quickly and produce high yields under specific geographical conditions would meet the demand for timber in many such areas and protect local endangered trees, which often include unique or rare species.

Grammar notes: The backbone of this sentence is Introducing genetically modified trees would satisfy the demand for wood and save the endangered native trees. Introducing genetically modified trees at the beginning of the sentence is a gerund, serving as the subject, in which the past participle modified serves as a prepositional attributive to modify trees; the past participle phrase designed for fast growth and high yield in given geographic conditions serves as a non-restrictive attributive, modifying genetically modified trees. The non-restrictive attributive clause introduced by which at the end of the sentence modifies the endangered native trees in front of it.

In the 1760s, James Watt perfected a separate condenser for the steam, so that the cylinder did not have to be cooled at every stroke; then he devised a way to make the piston turn a wheel and thus convert reciprocating (back and forth) motion into rotary motion.

In the 1760s, James Watt perfected the separate steam condenser, so that the cylinder did not have to be cooled after each stroke; he then invented a new method to allow the piston to rotate, that is, from the original ( Back and forth) reciprocating motion evolves into rotational motion.

Grammar Note: This sentence contains two parallel clauses, connected by a semicolon. The stem of the first clause is James Watt perfected a condenser; so the stem of the resulting adverbial clause that introduces is the cylinder did not have to be cooled. The backbone of the second clause is "He devised a way and convert ... into ...", where a way to do sth. is a fixed collocation, meaning "a way of doing something", convert sth. into sth . is also a fixed collocation, meaning "to transform... into...", and reciprocating is used as the present participle to modify the following noun motion.

Unlike short-term financial cooperation between investors for a single commercial undertaking, joint-stock companies provided permanent funding of capital by drawing on the investments of merchants and other investors who purchased shares in the company.

Unlike a short-term syndicate of investors with the aim of a single business project, a joint-stock company provides long-term funding by leveraging investments from businessmen and other investors who purchase shares in the company.

Grammar notes: The backbone of this sentence is Joint-stock companies provided permanent funding of capital. The following "by drawing on... in the company" is an adverbial of manner, which contains an attributive clause introduced by who to modify investors. The "unlike short-term... undertaking" at the beginning of the sentence serves as the comparative adverbial of the entire sentence.

This was justified by the view that reflective practice could help teachers to feel more intellectually involved in their role and work in teaching and enable them to cope with the paucity of scientific fact and the uncertainty of knowledge in the discipline of teaching.

This is reasonable because it is thought that reflective practice can help teachers engage more rationally in their role and teaching work, enabling them to cope with the lack of scientific facts in teaching guidelines and the uncertainty of knowledge.

Grammar notes: The backbone of this sentence is this was justified by the view. The clause "that practice could help ... in the discipline of teaching" serves as an appositive clause to explain the view. The subject of the appositive clause is reflective practice, and the predicate verbs are could help and enable; among them, the adjective involved in the past participle form of feel more intellectually involved in their role is used as the predicate of feel; cope with is followed by and to connect the paucity of scientific fact. and the uncertainty of knowledge in the discipline of teaching.

There were no other large public buildings, suggesting that the priests who were in charge of the temples also were responsible for governing the city and organizing people to work in the fields and on irrigation projects building and maintaining systems of ditches and dams.

There were no other large public buildings, which meant that the priests in charge of the temples were also responsible for running the city, organizing people to work in the fields, building water conservancy projects, and maintaining the system of ditches and dams.

Grammar notes: The backbone of this sentence is There were no other large public buildings. In the sentence, "suggesting that... ditches and dams" is used as an accompanying adverbial; following suggestion is an object clause that guides that. The backbone of the object clause is "The priests were responsible for governing... and organizing... and maintaining... ."; the attributive clause who were in charge of the temples modifies the priests; in the fields and on irrigation projects building are parallel structures connected by and, and together they serve as the adverbial adverbial of work.

Inequalities of wealth and rank certainly exist, and have probably existed in most pastoralist societies, but except in periods of military conquest, they are normally too slight to generate the stable, hereditary hierarchies that are usually implied by the use of the term class.

Inequality in wealth and status does exist, and probably exists in most nomadic societies. But except in periods of military conquest, such inequalities are usually too slight to form the kind of stable, hereditary hierarchy to which the word "class" is often used to imply.

Grammar notes: But in this sentence connects two sentences. The subject of the first sentence is inequalities of wealth and rank, and there are two coordinating predicates in the sentence, namely exist and have probably existed. The backbone of the second sentence is that they are too slight to generate hierarchies, where they refer to inequalities of wealth and rank, and the attributive clause that is usually implied by the use of the term class modifies the preceding hierarchies.

Many ecologists now think that the relative long-term stability of climax communities comes not from diversity but from the “patchiness” of the environment; an environment that varies from place to place supports more kinds of organisms than an environment that is uniform.

Many ecologists now believe that the relatively long-term stability of the climax community does not come from diversity, but from the "patch" of the environment. A changing environment is more conducive to the survival of a variety of organisms than a consistent environment.

Grammar Notes: The stem of this sentence is "Ecologists think that...". The object clause introduced by that contains two clauses: the backbone of the first clause is "The stability comes not from ... but from ..."; the backbone of the second clause is "An environment supports more kinds ... than an environment ...", the two environments in the second clause are both followed by an attributive clause leading to that, namely that varies from place to place and that is uniform.

According to conventional theory, yawning takes place when people are bored or sleepy and serves the function of increasing alertness by reversing, through deeper breathing, the drop in blood oxygen levels that are caused by the shallow breathing that accompanies lack of sleep or boredom.

According to traditional theory, people yawn when they are bored or sleepy. The shallow breathing associated with lack of sleep or boredom will reduce the oxygen content in the blood. Yawning can reverse the decrease in oxygen content in the blood through deep breathing, thereby improving alertness. The role of sex.

Grammar Notes: The backbone of this sentence is Yawning takes place and serves the function. "When people are bored or sleepy" in the sentence is an adverbial clause of time; "by doing" is a fixed collocation, meaning "by doing..." and is used as an adverbial clause of manner. The attributive clauses that are caused by the shallow breathing and that accommodations lack of sleep or boredom modify the drop in blood oxygen levels and the shallow breathing respectively.

Contrary to the arguments of some that much of the Pacific was settled by Polynesians accidentally marooned after being lost and adrift, it seems reasonable that this feat was accomplished by deliberate colonization expeditions that set out fully stocked with food and domesticated plants and animals.

Some believe that much of the Pacific was settled by Polynesians who accidentally got stranded here after getting lost and drifting. Contrary to this claim, this achievement was achieved through well-thought-out colonizing expeditions, well-prepared and well-laden with food, cultivated plants, and domesticated animals.

Grammar Notes: The backbone of this sentence is It seems reasonable that. that introduces a subject clause whose backbone is This feat was accomplished by colonization expeditions. After expeditions, there is an attributive clause that introduces that. The past participle phrase stocked with food and domesticated plants and animals in the clause serves as an adverbial in the clause, indicating the accompanying state. The adverbial "contrary to ... lost and adrift" at the beginning of the sentence contains an appositive clause "that much of the Pacific ... adrift" that introduces that, which is used to explain the arguments. The past participle phrase in the clause accidentally marooned Use it as a postpositional attributive to modify Polynesians.

The Athenian philosopher Socrates (470-399 B.C.) was the first person in Greece to propose a morality based on individual conscience rather than the demands of the state, and for this he was accused of not believing in the city's gods and so corrupting the youth , and he was condemned to death.

The Athenian philosopher Socrates (470-399 BC) was the first person in Greece to propose a moral code based on individual conscience rather than the requirements of the state. For this, he was accused of not believing in the gods of the city-state and thus corrupting the youth. Sentenced to death.

Grammar notes: This sentence is connected by two ands to three parallel clauses. The main stems of these three clauses are "Socrates was the first person to propose a morality", "He was accused of...", " He was condemned to death". The past participle phrase in the first clause modifies morality based on individual conscience rather than the demands of the state. In the second clause, “be accused of doing sth.” is a fixed collocation, meaning “to be accused of doing something.” Not believing in the city’s gods and corrupting the youth are co-ordinate components connected by and.

Two additional kinds of evidence support the hypothesis that petroleum is a product of the decomposition of organic matter: oil possesses optical properties known only in hydrocarbons derived from organic matter, and oil contains nitrogen and certain compounds believed to originate only in living matter

There are two pieces of evidence supporting the hypothesis that petroleum is a product of the decomposition of organic matter: the optical properties of petroleum are found only in hydrocarbons derived from organic matter; petroleum contains nitrogen and certain compounds that are thought to be derived only from biological sources .

Grammar notes: The backbone of this sentence is Two kinds of evidence support the hypothesis. The appositive clause "that petroleum is a product of..." explains the hypothesis. In the first clause after the colon "oil possesses ... organic matter", the past participle phrase known only in hydrocarbons modifies optical properties, and the past participle phrase derived from organic matter modifies hydrocarbons. In the second clause "oil contains ... in living matter", the past participle phrase believed to originate only in living matter modifies certain compounds.

Though it may be difficult to imagine from a later perspective, a strain of critical opinion in the 1920s predicted that sound film would be a technical novelty that would soon fade from sight, just as had many previous attempts, dating well back before the First World War, to link images with recorded sound.

Although it may have been difficult to imagine from a later perspective, in the 1920s, one critical opinion predicted that the technological novelty of talkies would quickly fade into obscurity, just as it had before - dating back to the first time. Before the World Wars - many attempts were made to link images and recordings together.

Grammar notes: The backbone of this sentence is "A strain of opinion predicted that...". That introduces an object clause, which contains an attributive clause that introduces that would soon fade from sight, modifying a technical novelty. After that, there is an adverbial clause "as had many... recorded sound" introduced by as, and as means "just like, like, and...the same". The present participle phrase dating well back before the First World War is used as a postpositional attributive to modify many previous attempts.

In the multiplicity of small-scale local egalitarian or quasi-egalitarian organizations for fellowship, worship, and production that flourished in this laissez-faire environment, individuals could interact with one another within a community of harmony and ideological equality, following their own popularly elected leaders and governing themselves by shared consensus while minimizing distinctions of wealth and power.

Small local egalitarian or quasi-egalitarian organizations of friendship, worship, and production thrive in a laissez-faire environment in which individuals can work together in harmonious and ideologically egalitarian communities. Influence each other, follow their own popularly elected leadership, and govern themselves through consensus while minimizing differences in wealth and power.

Grammar notes: The backbone of this sentence is Individuals could interact with one another. The prepositional phrase "in the multiplicity ... in this laissez-faire environment" serves as the adverbial of the entire sentence, which contains an attributive clause "that flourished in this laissez-faire environment" that introduces "that flourished in this laissez-faire environment" to modify organizations. The present participle phrase at the end of the sentence, following their own popularly elected leaders and governing themselves by shared consensus, serves as an accompanying adverbial. The time adverbial introduced by while omits individual were.