What tense is applied to English sentences when they appear before

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Before is preceded by the simple present tense. Before is usually in the past tense if it is followed by a sentence, in the simple past tense or in the past perfect tense.

If the verb is added directly, it is followed by the ing form. Used as a conjunction to guide the temporal adverbial clause.

Except for "in......In addition to the basic meaning of "before", the following usage is worth noting:

1) means "rather......I don't want to". As.

they would die before surrendering.They would rather die than give in.

2) means "less than ......It's not ...... yetjust". As.

before the week was out, they were dead.They died before the week was over.

3) It means "so as not to be" and "not to". As.

do it before you forget.Do it before it's too late, so you don't forget.

4) Indicates "(must) ...... firsttalents". As.

the wrecked car had to be lifted before the driver could be extricated.The crashed car had to be removed before the driver could be rescued.

5) means "(how long) to" "(how long) to". As.

itwon’tbelong before they understand each other.It won't be long before they get to know each other.

Before as a single adverb, that is, when used alone, it is often used in the present perfect tense and can also be used in the past tense. The before tense conjunction "before'' indicates the order of action of the main clause and the clause. The past perfect tense can be used in either the main clause or the clause with the same meaning.

For example: Before he entered the institute, he had served in the armyBefore he entered the institute, he served in the army.

If the before clause uses the simple past tense, the main clause can use the simple past tense or the past perfect tense with the same meaning.

For example: The concert had started before we got to the hallBefore we reach the lobby, the meeting has already begun.

1. Used as a preposition, pay attention to the following usage:

1. It means time, which means "in.".Before", and then can only be connected to point time or other nouns with point time meaning, but not for a period of time. Such as trembling: i'll be back before fiveo'clock。

I'll be back before 5 o'clock.

2. It means to choose one of the two, which means "rather..."And unwilling....”。For example: they would die before surrenderingThey would rather die than surrender.

2. An adverbial clause used as a precedent temporal conjunction

In addition to expressing "before....In addition to the basic meaning, the following usages are worth noting:

1) means "rather......I don't want to". For example: they would die before surrenderingThey would rather die than give in.

2. Representation"Less....just". "Not yet....just". For example: before the week was out, they were deadThey died before they had finished the cave that week.

Before as an adverb of a single big positive one, that is, when used alone, it is often used in the present perfect tense and can also be used in the simple past tense. before tense.

When the conjunction before indicates the order of action of the main clause and the clause, the past perfect tense can be used for the main clause, and the regret can be used for the clause with the same meaning. For example:

before he entered the institute,he had served in the army.

If the before clause is in the simple past tense, then the main clause can be in the simple past tense or the past perfect tense with the same meaning.

theconcert had started before we got to the hall.

Before as a single adverb, i.e., when used alone, it is often used in the present perfect tense and can also be used in the simple past tense. before tense.

When the conjunction before indicates the sequence of actions of the main clause and the subordinate clause, the past perfect tense can be used for both the main clause and the subordinate clause with the same meaning. For example:

before he entered the institute,he had served in the army.

If the before clause is in the simple past tense, then the main clause can be in the simple past tense or the past perfect tense with the same meaning.

theconcert had started before we got to the hall.