VERB FORMS

SEQUENCE OF TENSES (Sự hòa hợp giữ các thì)
1. Sự phối hợp của động từ trong mệnh đề chính (main clause) và mệnh đề phụ (subordinate clause)
Main clause
Subordinate clause

1. Simple present
- Simple present
- Present perfect
- Present continuous
- Simple future/ Near future
- Simple past (có thời gian xác định ở quá khứ)

2. Simple past
- Simple past
- Past perfect
- Past continuous
- Would/ was / were+ going to + V bare infi.
- Simple present (diễn tả một chân lý)

3. Present perfect
- Simple present

4. Past perfect
- Simple past

Eg: 1. People have said that Lon Lon has fog
2. Mary said that she was cooking them
3. He says he was born in 1980
4. Tom says he will visit me again.
2. Sự phối hợp của các động từ trong mệnh đề chính và mệnh đề trạng ngữ chỉ thời gian (adverbial clause of time):
Main clause
Adverbial clause of time

1. Present tenses
- Present tenses

2. Past tenses
- Past tenses

3. Future tenses
- Present tenses

Eg: 1. You will go home as soon as you have finished your exercises.
2. When I came there, it was raining hard.
3. I often drink coffee while I am watching TV.
4. Please wait here until I come back.
5. He never goes home before he has finished his work.
6. It was raining hard when I got there.
7. I had just come when you called.
* Mệnh đề trạng ngữ chỉ thời gian thường bắt đầu với các từ nối sau:
- When / as: Khi - as soon as: Ngay sau khi - as long a: chứng nào - just as: Ngay khi
- Until/ till: Cho đến khi - since: kể từ khi - while: trong khi - whenever: bất cứ khi nào
- before: trước khi - after: sau khi - no sooner …. than: ngay khi - hardly … when: khó… khi
- By the time: vào lúc ……………

* Note:
- Không được dùng thì tương lai (Future tense) trong các mệnh đề trạng ngữ chỉ thời gian (có thể thay bằng thì hiện tại)
Eg: If it rains tomorrow, we’ll stay at home.
- Trong trường hợp dùng từ nối “SINCE” chú ý:
S +V ( present perfect/ present perfect cont.) + Since + S + Ved.
Eg: You have been studying English since you came here.
EXERCISES:
Exercise 1: Choose the most correct answer:
He said that he ____ a lot of money on advertising to expand his business.
A. spends B. has spent C. spending D. had spent
The train _____ when we got to the station.
A. just left B. just leaves C. had just left D. will leave
Tom told me he _____ call me at the airport when I ______.
A. would/ arrived B. will/ arrive C. will have/ arriving D. would be/ arriving
At this time tomorrow, we ____ our final exam.
A. will have taking B. will be taking C. will be taken D. would take
-____ before? – Yes, I ____ my holidays here last year.
A. have you ever been / spent B. have you ever been / spend
C. Did you ever be / spending D. were you ever / spend
______ I was working in the garden, John was repairing the washing machine.
A. as soon as B. because of C. while D. until
Peter said he _____ a test the following day.
A. had had B. will have C. has had D. would have
After she _____ at the hospital for 2 years, she_____ to give up the job yesterday.
A. had been working/ decides B. had been working/ decided
C. working / had decided D. is working/ will decide
Tom _____ before we arrive there.
A. has left B. had left C. will leave D. leaves
In 1970, the Canadian scientist George Kelly ______ that warm water _____ more quickly than cold water.
A. prove/freeze B. proves / breezed C. proving / freezing D. proved/freezes
After we _____ our work, we ____ for lunch.
A. having finish/ went B. have finished/ went C. had finished/went D