I. Chuyển các câu sau từ câu chủ động sang câu bị động:
1. How many languages do they speak Canada?
2. Did Mary buy this beautiful dress?
3. Have the thieves slolen the most valuable painting in the national museum?
4. How many times have I told you to keep silent in class?
5. Are you going to help her solve that problem?
6. How did you find the keys in such a dark and messy room?
7. Have you turned of the air-conditioner?
8. When will you hand in the required assignment?
9. Should I send a complaint letter to the mayor?
10. Had you come to any conclusions before we came?
11. The students found the lecture boring.
12. The council considered the decrease in youth literacy rate the most alarming issue.
13. They reported that five men were injured in that accident.
14. They said those people are admirable.
15. They collect garbage on the beach every morning.
16. My sister sent me a gift on my birthday.
17. The waitress didn't bring me the dish I ordered.
18. Nguyen Thi Anh Vien broke Southeast Asian Games record on August 21st.
19. My father believes I will follow his advice.
20. My parents didn't allow me to play by the river.