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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21. It's 30 years since my father worked as an engineer. 

22. This is the first time Elsa has spent her summer in such a beautiful city.

EX3:

1. Tom hasn't come back to his hometown for 5 years.

2. He has worked as a teacher for 6 months.

3. We have not gone to Japan for 3 years.

4. I haven't had my hair cut since June.

5. We haven't met for 2 years.

6. We haven't called each other for a long time.

7. How long have you had 10 scores in Math?

8. I have never had such an exciting trip before.

`color{orange}{~MiaMB~}`