36. B. Many tourists visit Hanoi every year.
37. D. Why don't we sing an English song?
38. C. Their house will be built by them next month.
39. A. The train was late because the fog was thick.
40. C. In spite of getting up early, he was late for the first train. 
41. B. I have studied English for three years.

1. A. excited
2. D. pear
3. D. many
4. B. crossed
5. A. favorite
6. C. cloth
7. B. monthly
8. B. there
9. A. plays
10. D. future
11. C. riding
12. D. will be used
13. D. fly
14. C. flying
15. B. used to
16. B. although
17. A. so
18. D. across
19. B. although
20. B. won't be working
21. A. although
22. D. signs
23. B. the noise
25. B. any
26. C. do
27. B. unsafe
28. C. go
29. B. stand
30. C. was finished
31. C. eaten
32. A. grows
33. A. planted
34. B. beautiful
35. A. however