1.We have learnt English for 4 years.

we started to learn english 4 years ago

2. Ly's father started to give up smoking last year

-> ly's father has not smoked since last year.

3. The editor hasn't written to Mai for a month

-> the editor last wrote to Mai a month.

4. How long have you learnt Spanish

-> how long ago did you start to learn French?

5.They finished their exercises on time yesterday

-> Their exercises were finished on time yesterday.

6. A friend sold me a rock concert ticket last week.

-> a rock concert ticket was sold for me by a friend last week. 

7. The dentist took out one of my teeth three days ago

-> one of my teeth was taken out by the dentist three days ago.

Bài này mk làm rồi, yên tâm nha, xin hay nhất!

1.We have learnt English for 4 years.

→we started to learn english 4 years ago

2. Ly's father started to give up smoking last year

→ ly's father has not smoked since last year.

3. The editor hasn't written to Mai for a month

→the editor lastwrote to Mai a month.

4. How long have you learnt Spanish

→ how long ago did you start to learn French?

5.They finished their exercises on time yesterday

→ Their exercises were finished on time yesterday.

6. A friend sold me a rock concert ticket last week.

→ a rock concert ticket was sold for me by a friend last week. 

7. The dentist took out one of my teeth three days ago

→ one of my teeth was taken out by the dentist three days ago.