Chuyển sang câu bị động

Mng giúp mình vs 2h mình phải đi hc nào 2 bài này mình kbt lm =(((
Chuyển sang câu bị động ạ !
1. I have already watched the play before.
2. The 1999 flood has destroyed our city.
3. He has used his pencil instead.
4. This is the first time I have seen such a lovely dog.
5. The student hasn't done the homework yet.
6. They have taken her to the hospital.
7. They have cancelled the meeting.
8. Someone has moved my chair.
9. Someone has given him a lot of money.
10. We have invited all the students in the school.
11. We have told him not to be late again.
12. Our teachers have explained the English grammar.
13. Have you finished the above sentences?
14. The police have arrested the mugger,
15. The police have arrested five suspects
EXERCISE 6. Past perfect tense
1. They had finished doing their homework before they went to the cafeteria.
2. Her husband had done the housework before 7 party yesterday.
3. Before going shopping yesterday, David had cleaned the kitchen.
4. Wonbin had played the video game for four hours.
5. Ms Nina hadn't seen the film before.