5. Indicates arranging or planning future actions (generally limited to certain actions indicating movement, such as go, come, arrive, leave, begin, start, etc.), this arrangement is very fixed and not easy to change

4. Express future actions in time and conditional adverbial clauses (for example, if/as soon as, etc. are used to introduce the subject and the present)

1. Indicates existing habits, frequently occurring actions or existing states.

2. Indicate the subject’s characteristics, personality, abilities, etc.

3. Express objective facts or universal truths

often, usually, every..., sometimes, always, never, seldom, once/twice/…aweek/month/year, on Sunday/Monday…

1. Use am/is/are for the verb be, followed by n./a./prep.

2. Use V./V.-s,-es for action verbs

A) Pay attention to the collocation of time adverbials. Generally, the time adverbial in the past tense should be a word or phrase that expresses a certain time in the past, such as: yesterday, last month, in 1999, two days ago, etc. It must not be used with recently, in the past 10 years, this month, etc., because Such time adverbials are related to the present, and should be used in the present perfect tense or present simple tense.

B) The negative and interrogative forms of used to do are very special: no matter how you write it, it is correct. Take the negative form as an example: used not to do, didn't used to do, didn't use to do are all correct. Used to do is often contrasted with the be used to doing sth/ sth structure. The former means "often or in the past", requiring the addition of the verb base form; the latter means "used to", requiring the addition of a noun or gerund

6. Used in a special structure [Note] This usage is mainly used for It's (high) time...;I wish...;I'd rather...;if only;as if;as though, etc. A small number of structures followed by clauses

5. Express politeness and tactful present [Note] The verbs that can be used in this way are mainly limited to a few verbs such as want, wonder, think, hope, and intend.

8. When the predicate verb in the main clause is in the present perfect tense, the clause introduced by since uses the past tense.

4. In the object clause, due to the echo of tenses, the past tense can be used to express the present.

7. Subjunctive conditionals expressing subjective thoughts also use the past tense to express the present.

3. Indicates actions that occurred frequently or repeatedly in the past period of time

2. Describe a continuous event in the past

1. Indicate past actions or states

yesterday, the day before yesterday, last week/month/year/…,…ago, a moment ago, just now, on/in past time

1. The verb be is expressed in the past tense was/were

2. Use V-ed for action verbs

4."be to do"

1. "be going to V." is mostly used in spoken language. It often expresses intention, upcoming, determination to do or something that may happen.

2. Go, come, leave, start and other verbs that express movement can be used to express upcoming actions in the present continuous tense.

3. "Be about to V." indicates an action that is about to happen, emphasizing what needs to be done in the near future or immediately.

In adverbial clauses introduced by conjunctions such as if, when, as long as, as soon as, after, before, in case, until, unless and adverbs with the function of conjunctions (immediately, the moment, directly), the present tense is generally used Replace the future tense. When emphasizing continuity or dynamics, use the perfect tense

tomorrow, the day after tomorrow, soon, next week/month/year/…after next, on/in future time, in a period of time

1. Indicate future action or status

2. To express an action that will occur frequently in the future.

1.will V.

2.is/am/are going to V.

Since the past tense is a combination of past tense and future tense, please refer to the relevant precautions for past tense and future tense.

Expressing an action or state of existence that will occur at a certain time in the past, commonly used adverbial clauses

1.was/were going to V.original form

2.would/should V.original form

2. Indicates an action or situation that started at a certain time in the past and has continued to the present, and is likely to continue. Continuous verbs are often used here. Time adverbials often use since plus a past time point, or for plus a period of time, or by plus a present time.

3. Indicates actions or situations that occurred in the past but still have an impact on the present. Usually use verbs, such as: arrive, begin, find, give, lose, etc.

1. Indicates that the action has been completed so far or has just been completed. In Chinese, it is often expressed with "了" or "了"

A) The present perfect tense is the link between the past and the present. The difference between the present perfect tense and the past tense is that the present perfect tense emphasizes the dynamics of the action, or is affected by dynamics, is the result of dynamics, and has an impact on the present; the past tense only expresses actions that occurred at a specific time in the past, and No contact now.

B) Because the perfect tense of time adverbials such as for plus a period of time or since plus a point in time has dynamic and continuous characteristics, terminal verbs or momentary verbs cannot be used.

E) In sentence patterns such as "no sooner than", "hardly/ scarcely...when", "before", "prior to", etc., the main clause requires the perfect tense

C) The perfect tense is required in the sentence pattern "this is the first/ second/ third... time that...".

D) Both tenses used in the sentence pattern "It is/ has been...since" are correct.

already, just, before, yet (in negative sentences), ever, never, since time point, for time period

have/has V. past participle

Indicates an action or state that starts at a certain time in the future and continues to another future time, or an action or state that occurs at a certain future time but has an impact on another future time. It's like moving the present perfect tense to the future tense period of the timeline. Its usage changed from relating to the past and present to relating to the future and the future of the future.

Since this tense is a fusion of future tense and perfect tense, you can refer to the relevant precautions for "simple future tense" and "present perfect tense" regarding the precautions for this tense.

will have V. past participle

Indicates an action that has occurred or a state that has existed before a certain time or action in the past. That's what we often say: expressing "past past action or state"

The logical relationship of "the past of the past" is often reflected through context and is not necessarily restricted by a certain time adverbial.

had V. past participle

1.should have done

2. would have done

1. The past and future perfect tense indicates that an action has been completed at a certain time in the future from the past point of view.

2. If the subjunctive mood expresses the opposite of a past fact, the predicate of the conditional clause uses the past perfect tense (had past participle), and the predicate of the main clause usually uses the past future perfect tense (would have past participle). Of course, the main clause The predicate can also use "should (could, might) have past participle" according to the situation

3. Sometimes it can express an action that will happen in the future, with the meaning of "intention" or "plan" (used for actions such as go, come, stay, leave, start, etc. that express movement)

2. Indicates an action that is currently taking place, although the action may not be taking place at this moment.

1. To express the action that is happening at this moment (when speaking)

now, at present, Look! (usually at the beginning of the sentence), Listen! (usually at the beginning of the sentence)

is/am/are V.ing

2. Past continuous tenses such as go, come, stay, leave, start, etc. that express movement can express actions that occurred in the past or future.

3. If one of the main clauses introduced by time adverbial introductory words such as when and while is the past tense, the other sentence often uses the past continuous tense.

1. Indicates actions that are taking place in the past period of time

at that time,at this time,yesterday,at time point yesterday/last night,at that moment

was/were V.ing

1. Indicates an ongoing action at a certain time or period of time in the future

2. Indicates actions determined by more objective circumstances in the future or actions that will occur according to arrangements

at this time future time point

Since this tense is a fusion of future tense and continuous tense, please refer to the relevant precautions for "simple future tense" and "present continuous tense" regarding the precautions for this tense.

will/shall be V.ing

should/would be V.ing

1. Indicates an ongoing action at a moment in the past or a certain period of time in the future

2. To express an action that is about to take place or is planned to take place after a certain period of time.

Compared with the present perfect tense, the present perfect continuous tense emphasizes more: in the time from the past to the present, the action or state has continued or has been recurring.

Indicates that an action started at a certain time in the past, continues or occurs repeatedly to this day, or will continue into the future.

have/has been V.ing

had been doing

Indicates an ongoing action or state in the past, which lasted until a certain moment in the past, has not yet been completed, and continues until the present time.

1.shall have been doing

2.will have been doing

Indicates that an action that has already started will continue at a certain future time

1.should have been doing

2.would have been doing

In indirect speech, if the main clause is in the past tense, the indirect speech used in the object clause must be changed from the future perfect continuous tense to the past future perfect continuous tense.