15. The letter are written to our friend.

16. The garages are cleaned everyday.

17. He has been given a lot of money by someone.

18. Two hundred people were arrested by the police.

19. This computer is exported to seventy different countries.

20. The meeting has been cancelled.

21. All the students have been invited in the school.

22. All the letters were posted yesterday.

23. Two children were found in the forest by the police.

24. A meeting will be held before May Day.

25. The cake is being cut with a sharp knife by Mary.

26. A story is going to be told by the teacher.

27. The town was destroyed by an earthquake.

Giải thích: Các cấu trúc câu bị động các thì

- Thì hiện tại đơn: S+am/is/are+V-pp

- Thì hiện tại tiếp diễn: S+am/is/are+being+V-pp

- Thì hiện tại hoàn thành: S+have/has+been+V-pp

- Thì quá khứ đơn: S+was/were+V-pp

- Thì quá khứ tiếp diễn: S+was/were+being+V-pp

- Thì quá khứ hoàn thành: S+had+been+V-pp

- Thì tương lai đơn: S+will+be+V-pp

- Thì tương lai tiếp diễn: S+will+be+being+V-pp

- Thì tương lai hoàn thành: S+will+have+been+V-pp

- Modal verbs: S+modal verbs+be+V-pp