I. Đổi sang câu bị động.

1. Did your friend mail that letter?...........................................................................................

2. Has Nina finished the work?...................................................................................................

3. Did he speak about tropical countries in the world?............................................................

. 4. Had your sister cleaned the floor when I came?.....................................................................

5. Does he make bad chocolate cake?........................................................................................

6. Must you post this letter?...................................................................................................

7. Have you taken my book?...........................................................................................

8. Can you clean the house?........................................................................................................

9. Does he steal my ruler?.......................................................................................................

10. Does your friend buy this house?.........................................................................................