1. Students are expected not to talk during the examination.

2. The bomb was being carried to a safe place when it exploded.

3. My chair has been moved.

4. The Smiths weren't invited to our party.

5. Tom wasn't allowed to take these books home.

6. The group of students' friend has been met at the railway station. (mình nghĩa a group thành the group bởi vì nó đã được xác định r á)

7. Exercises will not be corrected by the teacher tomorrow.

8. Many people are attracted by this well-known library.

9. The meeting was attended by all students.

10. Her bike can be repaired.

11. This is the second time we have been written to about this.

     We have been written to about this twice.

12. We have been taught French by Mr. Smith for 2 years.

13. The children weren't looked after properly.

14. A lot of tea was drunk in England.

15. The traffic laws must be obeyed.

16. Those oranges cannot be picked.

17. The floor was being cleaned.

18. They have been supplied with food.

19. The answers will not be found.

20. Rubbish weren't dumped into the river (by the villagers).

*Cấu trúc: 

S+V+O+(trạng từ chỉ nơi chốn)+(trạng từ chỉ tgian)

=> S(O)+be+P2+(trạng từ nơi chốn)+by+O(S)+(trạng từ tgian)

*Notes: 

- Tân ngữ của câu chủ động là people/ they/ someone/ somebody/ we/ ... thì chuyển sang bị động có thể bỏ đi.

- Adv tần suất "always/ often/ ..." đặt sau "tobe" và trước V.

- Adv tần suất "everyday/ once a week/ ..." đặt trước "by+O"