chuyển sang câu bị động; thì hiện tại hoàn thành 1. i have bought this teddy bear in that shop 2. vicky has found her hat 3. i have lost my bag 4.we have finished the report 5.i have done my exercise for three days 6. tom has seen this film before 7. nina has read the newspaper already 8.they have seen these movies yet 9. i have signed the contrac

1. this teddy bear has been bought  in that shop by me

2. vicky's hat has been found by her 

3. my bag has been lost by me

4. the report has been finished by us 

5.my exercise has been done by me for three days

6. this film has been seen by tom before

7. the newspaper has been read by nina already

8.these movies have been seen by them yet

9.  the contrac has been signed by me

Đáp án : 

1. This teddy bear has been bought in that shop 

2. Her hat has been found by Vicky 

3. My bag has been lost 

4. The report has been finished by us 

5. My exercise has been done by me for three days 

6. This film has been seen by Tom before 

7. The newspaper has been read by Nina already

8. These movies have been seen yet 

9. The contrac has been signed by me

Giải thích : sử dụng cấu trúc thì hiện tại hoàn thành ở câu bị động 

" S + HAS/ HAVE  + BEEN + QUÁ KHỨ PHÂN TỪ + BY +O "