3. The dinner is being preparing in the kitchen by mother.

4. Our teeth should been cleaned by us twice a day.

5. The English grammar has been explained by our teacher.

6. The accident was caused in this city by some drunk drivers.

7. His parents will be visited by Tom next month.

8. The secretary wasn't phoned by the manager this morning.

9. Was this beautiful dress by Mary?

10. These old pictures won't be hung in the living room by me.

11. This room may be used for the classroom.

12. The story is going to be told by the teacher.

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

14. The victims have been provided with food and clothing.

15. This machine musn't been used after 5. 30pm by you

Giải thích 

1. Tìm tân ngữ (là từ chỉ người / chỉ vật đứng sau V1)⇒ đưa lên đầu câu làm chủ ngữ

2. Tìm động từ: để lấy V đó à P₂

3. Đưa S xuống cuối câu à thành tân ngữ (nếu có trạng từ thời gian chuyển xuống cuối câu)

HT              ⇒  is/ are / am + P₂

QK              ⇒ was / were + P₂

HTTD          ⇒ is/ are / am + being + P₂

QKTD        ⇒ was /were + being + P₂

TL gần        ⇒ is/ are / am going to + be + P₂

HTHT          ⇒ has / have + been P₂

Modal V      ⇒ Modal V + be P₂

Modal V: can, will, would, may, could, might, must, ought to, have to / has to, should