1.1 Directly as the subject: To see is to believe.

1.2 it serves as the formal subject: It took me two weeks to finish the assignment.

2.1 As the object of transitive verbs, common verbs include: decide, tell, hope, agree, manage, etc.

2.2 it serves as the formal object: subject think/believe/make/find/ consider it adj/n to do sth

3.1 indicates further explanation of the subject and has future time meaning: His dream is to teach English.

3.2 means should; You are to report that to the police.

4.1Have you got anything to eat?

4.2 Ordinal numerals and superlative adjectives before the modified noun, the next, the only, the last and other modifications: She is the first person to come up with the solution.

4.3 Todo is often used to modify nouns such as ability, chance, opportunity, need, ambition, and attempt.

5.1 Adverbial phrase of purpose

5.2 Adverbials of result

5.3 Adverbials of reason

5.4 Commentary adverbials

6.1 Sensory/causal verb object object complement in todo infinitive to is omitted, but to should be restored in passive voice

1. When making prepositions but, except, besides, and than as objects, there is the substantive verb do before it, and there is no to after it; there is no do before, but there is to after it. For example: He did nothing but cry.

2. When making a predicate, if the subject part contains some form of the substantive verb do, then to is omitted. The only thing you can do is apologize.

be adj to do: This question is easy to answer.

1. He didn't know what to say.

2. How to learn English is hard.

3. The key step is to predict the end.

1.1 Represents a concept, habit or experience. A single gerund phrase serves as the subject, and the predicate verb uses the third person singular.

1.2 it serves as the formal subject and there be serves as the subject in the sentence pattern

2.1 Be the object of verbs and prepositions

3.1 Expresses abstract, general or habitual actions, indicating that the subject content can interchange positions with the subject. For example: My hobby is collecting stamps.

4.1 Table is the function or purpose of the modified noun. Equivalent to noun for doing

done

Present participle: expresses the characteristics of the subject

Past participle: expresses the feeling or state caused by the subject itself.

Present participle: active, ongoing

Past participle: transitive verbs express passive and perfect; intransitive verbs only express completion

The logical subject of time, cause, result, manner or accompanying, etc. must be consistent with the subject of the main clause. The present participle is the doer and the past participle is the recipient.

"Having done" is used as an adverbial, and it has an active relationship with the subject of the main clause logically, and the participle action occurs before the predicate verb of the main clause.

"Having been done" is used as an adverbial, and it has a logical passive relationship with the subject of the main clause, and the participle action occurs before the predicate verb of the main clause.

Being done is used as an adverbial, and has a logical passive relationship with the subject of the sentence, and occurs simultaneously with the predicate verb of the main sentence.

Often after the object of sensory verbs and causative verbs. The present participle indicates that the object is in progress, and the past participle indicates that the object has passive and perfect meanings.