Chuyên đề ngữ pháp: Sự phối hợp thì (The Sequence of Tense)

Một câu có thể bao gồm một mệnh đề chính (main clause) và nhiều mệnh đề phụ (subordinate clause). Khi trong câu có từ 2 mệnh đề trở lên, thì các động từ phải có sự phối hợp về thì.

1. Sự phối hợp của các động từ trong mệnh đề chính (Main clause) và mệnh đề phụ (Subordinate clause)

MAIN CLAUSE	SUBORDINATE CLAUSE
Present simple Future simple	Present tenses: + Present simple + Present progressive + Present perfect +Future simple am/is/are +going to +V( bare-inf) Past simple ( with specific time in the past)
Past simple	Past tenses: + Past simple + Past perfect + Past progressive Future in the past (would+ bare-inf) was/were + going to+ V (bare-inf) Present simple (describe a fact, a truth, or a habit at the present)
Present perfect	Present simple
Past perfect	Past simple

Ex:

I work so hard that I am always tired.

She will think that I have taken her book.

Tom promises that he will visit me.

He says that he is going to eat it.

She says that she was born in 1971.

2. We knew that the bridge was unsafe.

I thought that she was cooking then.

He saw that he had made a mistake.

We thought that it would rain.

My teacher said that the moon circles the Earth every 28 days.

3. I have forgotten what he looks like.

4. They had done all that was necessary.

2. Sự phối hợp của các động từ trong mệnh đề chính (Main clause) và mệnh đề trạng ngữ chỉ thời gian (Adverbial clause of time)

Mệnh đề trạng ngữ chỉ thời gian thường được bắt đầu bằng các liên từ chỉ thời gian như: when, while, whenever, as, before, after, as soon as, till, until, just as, since, no sooner… than, hardly… when, as long as, once, by the time,v.v

Main clause	Adverbial clause of time
Present tenses	Present tenses
Past tenses	Past tenses
Future tenses	Present tenses

Present tenses:

I usually eat popcorn while I am watching movies.

She never goes to work before she has taken a shower.

2. Past tenses:

He was cooking when I visited him.

When the police arrived, all of suspects had died.

He had no sooner arrived than he was asked to leave again.

3. Future tenses:

I will visit you when I have free time.

We will give you a call as soon as we arrive/ have arrived.

After she graduates, she will work in Mindshare.

Lưu ý:

Không dùng các thì tương lai trong các mệnh đề trạng ngữ chỉ thời gian, thì Simple Future được thay bằng Simple Present; thì Future Perfect hoặc Future Perfect Continuous được thay bằng Present Perfect hoặc Present Perfect Continuous.
Trong trường hợp dùng liên từ since phải lưu ý: Động từ trong mệnh đề chính thường được chia ở thì Present Perfect hoặc Present Perfect Continuous, động từ trong mệnh đề phụ có since thường được chia ở thì quá khứ đơn (past simple).

S+ V ( present perfect/ present perfect continuous) + since +S+V (past simple)

Ex: We haven’t seen her since she left school.

She has been playing tennis since she was eight.