What are the important grammars in English?

subjunctive mood

1) concept

Subjunctive mood is used to express the speaker's subjective wishes or assumptions, which is a condition, not necessarily a fact, or contrary to the fact.

2) Application in conditional sentences

Conditional sentences can be divided into two categories, one is true conditional sentences and the other is untrue conditional sentences. Unreal conditional sentences indicate hypothetical or unlikely situations, so subjunctive mood is adopted.

If the clause part of the subjunctive conditional sentence contains were, should and had, you can omit if, and then move were, should and had to the beginning of the sentence to realize inversion.

If they were here now, they would help us.

If you had come earlier, you would have met him.

If it rains, the crops will be saved.

note:

In the subjunctive clause, the past tense of the verb' be' is always' were' instead of' was', that is, be is replaced by' were' in the clause.

If I were you, I would go to him.

If he were here, everything would be fine.

Two imperative mood.

Imperative mood expressed advice, orders, hopes or prohibitions, etc. From the prototype verb, the subject is often omitted.

Give me some candy first.

Imperative mood requests, suggests or invites.

Be a good boy. Please tell me.

Please speak slowly.

Three ellipsis sentences

Ellipsis is a sentence that omits one or more sentence elements, such as subject, predicate verb or clause.

The subject of a sentence can be omitted without causing misunderstanding or informality.

It looks like rain.

The equivalent conjunction and connects two coordinate clauses. If the predicate verbs in the two sentences are the same, the verbs in the second sentence can be omitted.

I am a doctor and my wife is a teacher.

Four attributive clauses

attributive clause

1. The clause used as an adjective in the sentence is an adjective clause.

Adjective clauses can modify people or things and are connected by relative pronouns who, which and that.

The teacher scolded the boy who broke the window.

Breaking the window is an adjective clause that modifies a boy.

This must be a toy car that can be assembled.

This must be an assembled toy car.

That(which) can be assembled as an adjective clause that modifies toy cars.

He is reading a book written by Mark Twain.

This is written by Mark Twain, and it is an adjective clause that modifies a book.

Five adverbial clauses-adverbial clauses

1. A clause that acts as an adverb in a sentence is an adverb clause.

2. Adverb clauses indicate time.

I'll be back before dark.

After dark, the children went home.

The children went home after dark.

Six clauses are consistent with the antecedent.

1. The consistency between clauses and antecedents mainly refers to the consistency between the relative pronouns of adjective clauses and predicate verbs and the antecedents of main sentences.

2. When the relative pronouns who, which and that are used as subjects in adjective clauses, the person, sex, number and predicate verbs must be consistent with the antecedent.

I am your friend and can help you.

As your friend, I can help you.

Seven infinitives

The simple form of infinitive is composed of to+ prototype verbs, and its action occurs at the same time or after the active word.

I am glad to see you.

I'm glad to meet you.

He promised to raise money for us.

He promised to prepare funds for us.

Passive voice is not used as much as active voice, but it is necessary or appropriate to use it in some cases.

1. Use the passive voice when you don't know or need to specify the sender of the action.

He was born in 197 1.

The origin of the universe may never be explained.