1. By the time we arrived at the place, the man had left.

- Clause 1 (QKHT) + before + Clause 2 (QKĐ): trước khi

-> By the time + Clause 2 (QKĐ), Clause 1 (QKHT): Vào lúc

2. Minh has collected stamps since 2010.

- S + started/began + V-ing/ to V + in + năm (thời gian trong quá khứ)

-> S + have/has + V3/ed + since + mốc thời gian (thời gian trong quá khứ)

3. This is the first time I have seen such a beautiful painting.

- S + have/has + never + V3/ed + such + (a/an) + adj + N(s) + before

-> This is the first time + S + have/has + V3/ed + such + (a/an) + adj + N(s)

4. He has worked here since he was 20 years old.

- S + started/began + V-ing/ to V + when + QKĐ (S + was/were + N/Adj)

-> S + have/has + V3/ed + since + QKĐ (S + was/were + N/Adj)

5. It is ages since John and Marry got married.

- S + have/has + V3/ed + for + khoảng thời gian

-> It is + khoảng thời gian + since + S + V2/ed

6. She last had a swim five years ago.

- S + haven't/hasn't + V3/ed + for + khoảng thời gian

-> S + last + V2/ed + khoảng thời gian + ago

7. They haven't talked to each other for two months.

- S + last + V2/ed + khoảng thời gian + ago

-> S + haven't/hasn't + V3/ed + for + khoảng thời gian

8. John has had his hair cut for over six months.

- It is + khoảng thời gian + since + S + V2/ed

-> S + have/has + V3/ed + for + khoảng thời gian

9. When did he last write to you?

- How long is it + since + S + V2/ed?

-> When + did + S + last + V(bare)?

10. I haven't had a good night sleep for ten weeks.

- It is + khoảng thời gian + since + S + last + V2/ed

-> S + haven't/hasn't + V3/ed + for + khoảng thời gian

Các công thức đổi HTHT - QKĐ

Structure 1: 

S + has/have + not + V3/ed + for/since + time 

--> S + last + V2/ed 

--> The last time + S+ V2/ed + was + time 

--> It is / has been + time + since + S+ (last) + V2/ed 

Structure 2: 

How long + has/have + S+ V3/ed?

--> When + did + S + V1?

--> How long is it + since + S+ V2/ed ?

Structure 3:

S + has/have + V3/ed + for/since + time 

--> S + started / began + to V / Ving 

--> It is / has been + time + since + S+ V2/ed 

Structure 4: 

S + has/have + not/never + V3/ed + ... before

--> This/It is the first time + S+ has/have+ V3/ed

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1. By the time we arrived at the place, the man had left.

By the time + QKD, QKHT

2. Minh has collected stamps since 2010.

3. This is the first time I have ever such a beautiful painting.

4. He has worked here since he was 20 years old.

5. It is ages since John and Mary got married.

6. She last had a swim five years ago.

7. They haven't talked to each other for two months.

8. John hasn't had his hair cut for over six months.

9. When did write to you?

10. I haven't had a good night sleep for ten weeks.

`color{orange}{~MiaMB~}`