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. Samuel has kept a diary since 1997.

2. She started to teach the children in this remote village five months ago.

3. The last time he wrote to me was in April.

4. She last had a swim five years ago.

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

6. She hasn't seen her elder sister since 1999.

7. It's years since she last wrote to me.

8. It's ten years since Robert and Catherine got married.

9. They haven't cleaned their room for two weeks.

`color{orange}{~LeAiFuRuiHuiBao~}`

S + started + Ving + thời gian + ago

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

S + have/has + not + V3/ed + for + khoảng thời gian

`->` The last time + S + V2/ed + was + thời gian + ago