Đáp án:

1. Selina has played the piano for 10 years.

2. My father started taking his new job in Feburary.

3. Her brother has given up smoking since he had a child.

4. She last attended a party 5 months ago.

5. It's the first time we have played hide-and-seek.

6. I have never worn a dress before.

7. He is the gentlest man I have ever met.

8. I haven't taught such a smart girl before.

9. It's 2 days since I last watched a film.

10. The last time Lan took a shower was last Friday.

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Các công thức đổi HTHT - QKĐ

Type 1: 

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

--> S + last + V2/ed 

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

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

Type 2: 

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

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

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

Type 3:

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

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