1 .The telephone was invented by Graham Bell many years ago.

2. I was sent this letter by Mary two days ago.Subject:Mary

3.A strange man was seen by me in the garden yesterday

4.These cars were made in the USA

5. Many trees were planted in the school garden

6. I wasn't helped with my homework.

7.Some comic books were bought for Lan's brother.

8.A letter was received yesterday.

9.trùng câu 6

10.trùng câu 7

11.trùng câu 8

12.The new pupil was told where to sit

13.The room was filled by smoke

14.Two criminals were arrested by the police last night

15.sửa đề:

fortunately they didn't damage the machinery

=>Fortunately the didn't damage the machinery.

16.We were asked many difficult questions

17.I was advised to use milk bottles by her.

18. Her sister was taught English by her last year.

19.The window is opened by Anna

20. Was this circle drawn by Sue?

Công thức câu bị đông:S+be+v3ed+by O

Công thức câu bị động quá khứ đơn :S+was/were+v3/ed+by O