11. Why didn't you report the accident sooner? => Why wasn't 

12. I could hear someone crying in the next room.=> Someone

13. Jack saw the car drive up outside the police station. => The car 

14. We overheard them say that they didn't really like the food. => They were 

15. I expect you to find your money somewhere in your bedroom. => l expect 

16. Jane has just begun learning English for 2 weeks. => English 

17. People continue to use Facebook as a main way of socializing. => Facebook 

18. They are going to employ someone to repair the roof. => They 

19. It's your duty to type the report before the meeting. => You 

20. I suggested putting the matter to the committee. => l suggested 

21. It's everyone's duty to collect the litter in  publi

Answer:

11. Why wasn't the accident reported by you sooner?

12. Someone could be heard crying in the next room by me.

13. The car was seen to drive up outside the police station by Jack.

14. They were overheard to say that they didn't really like the food.

15. I expect your money to be found somewhere in your bedroom by you.

16. English began being learnt by Jane for 2 weeks.

17. Facebook continues to be used as a main way of socializing (by people).

18. They are going to have the roof repaired (by someone).

19. You are supposed to type the report before the meeting

20. I suggested the matter should be put to the committee.

21. Everyone is supposed to collect the litter in public.

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Công thức Bị Động:

11. Why + was/were + S + Ved/V3 + By O + time?

- Ved/V3 => was/were + Ved/V3

12. S + could + be + Ved/V3 + by O + time

- Can/could + V-inf => Can/could + be + Ved/V3

13. S + tobe + seen + to V/V-ing + by O + time

- see + O + V-inf/V-ing + O => tobe seen + to V/Ving

14. S + tobe + overheard + to V + O.

15. S + expect + sth + to be done + by O

16. S + began + to be Ved/V3 + by O + time

17. S + continue to + be Ved/V3 + by O + time

18. S + am/is/are + going to + have + sth + Ved/V3 + by O + time

19,21. It's your duty to do sth

-> You are supposed to do sth

20. S + suggested + sth + should + be Ved/V3 + by O + time

Chúc bạn học tốt

`11.` Why didn't you report the accident sooner? ⇒ Why wasn't the accident reported sooner?

- Cấu trúc CBĐ đối với dạng câu hỏi Wh thì QK: Wh + was (not) /were (not) + S + V3?

`12.`  I could hear someone crying in the next room. ⇒ Someone could be heard crying in the next room.

 - Câu bị động với động từ khuyết thiếu: S + could be + V2

`13.` Jack saw the car drive up outside the police station. ⇒ The car was seen to drive up outside the police station by Jack. 

- Cấu trúc CBĐ chỉ giác quan (see, hear, watch, look,...) : S + to be + V2 + to V/V-ing + O

- Động từ "drive up" ở câu chủ động giữ nguyên thể ⇒ CBĐ chọn "to drive up"

`14.` We overheard them say that they didn't really like the food. ⇒ They were overheard to say that they didn't really like the food.

- overheard: nghe lén

- Tương tự câu `13` 

`15.` I expect you to find your money somewhere in your bedroom. => l expect your money to be found somewhere in your bedroom.

- Cấu trúc CBĐ với expect: S + expect + O + to be + V2

`16.` Jane has just begun learning English for 2 weeks. ⇒ English has just been begun to be learned by Jane for 2 weeks.

- Cấu trúc CBĐ: S + be + V2 + byO

`17.` People continue to use Facebook as a main way of socializing. ⇒ Facebook is continued to use as a main way of socializing.

- Cấu trúc CBĐ: S + be + V2 + byO

`18.` They are going to employ someone to repair the roof. ⇒ They are going to have someone repair the roof.

- Cấu trúc have sb V: nhờ ai đó làm gì

`19.` It's your duty to type the report before the meeting. ⇒ You are supposed to type the report before the meeting.

- Cấu trúc You are supposed to do sth: Bạn được giao nvu làm gì

`20.` I suggested putting the matter to the committee. ⇒ l suggested the matter should be put to the committee.

- Cấu trúc S + suggested (that) + sth + (should) be + V2

`21.` Thiếu đề bài