1. We should clean these windows before tomorrow.

-> These windows should be cleaned before tomorrow

2. The workers gave the boss some flowers.

-> The boss was given some flowers by the workers

3. The police followed the thieves into a building.

-> The thieves were followed into a building by the police

4. The mechanic can' t fix my car.

-> My car can't be fixed by the mechanic

5. The neighbour has told us the news.

-> We have been told the news

6. The students painted the walls last year.

-> The walls were painted by the students last year

7. The old woman feeds the pigeons every day.

-> The pigeons are fed by the old woman everyday

8. They will pick up John at this office.

-> John will be picked up at this office

9. She showed the visitors the new house.

-> The visitors were shown the new house by her

10. You shouldn't throw litter on the ground.

-> Litter shouldn't be thrown on the ground

11. The teacher asked the students a very difficult question at the oral exam.

-> The students were asked a very difficult question at the oral exam

12. First, we have to read the text and then, we have to do the exercises.

-> First , the text have to be read and then , the exercises have to be done

13. His parents promised Tom a hundred Euros if he passed the test.

-> Tom was promised a hundred Euros if he passed the test by his parents

14. Did they repair all the windows?

-> Were all the windows repaired ?

15. The news surprised us all.

-> We were all surprised by the news

16. Is the teacher correcting the exams right now?

-> Are the exams being corrected by the teacher right now ?

17. Someone has sent John a mysterious letter.

-> John has been sent a mysterious letter

18. Where did they find the book?

-> Where was the book found ?

19. The taxi driver drove us to the airport.

-> We were driven to the airport by the taxi driver

20. Many people have seen a UFO in this area.

-> A UFO has been seen in this area

21. Have they watered the plants ?

-> Have the plants been watered ?

22. Someone stole my purse while I was doing the shopping.

-> My purse was stolen while the shopping was being done

23. The secretary has already sent all the documents to Mr. Smith.

-> All the documents have already been sent to Mr.Smith by the secretary

24. They have offered Michael an excellent job in a British company.

-> Michael has been offered an excellent job in a British company.

25. The police could arrest the bank robbers when they were crossing the border.

-> The bank robbers could be arrested when they were crossing the border

26. Someone has used the computer without perminsion.

-> The computer has been used without permission

27. My grandmother is baking a delicious cake.

-> A delicious cake is being baked by my grandmother

p/s : Phù!!!Mỏi cả tay :))

1. These windows should be cleaned by us before tomorrow.
2. The boss was given some flowers by the workers.
3. The thieves were followed into a building by the police.
4. My car can't be fixed by the mechanic.
5. We have been told the news.
6. The walls were painted by the students last year.
7. The pigeons were fed by the old woman every day.
8. John will be picked up at this office.
9. The visitors were shown the new house.
10. Litter shouldn’t be thrown on the ground.

11. The students were asked a very difficult question at the oral exam.
12. First, the text has to be read, and then, the exercises have to be done.
13. Tom was promised a hundred Euros if the test was passed.
14. Were all the windows repaired?
15. We were surprised all by the news.
16. Are the exams being corrected right now?
17. John has been sent a mysterious letter.
18. Where was the book found?
19. We were driven to the airport.
20. A UFO has been seen in this area.

21. Have the plants been watered?
22. My purse was stolen while the shopping was being done.
23. All the documents have already been sent to Mr. Smith.
24. Michael has been offered an excellent job in a British company.
25. The bank robbers could be arrested when the border was being crossed.
26. The computer has been used without permission.
27. A delicious cake is being baked.