=>
19. B is
20. D with
21. A take
22. A can S V
23. C at the moment -> HTTD
24. D go camping : đi cắm trại
25. A x

26. B yesterday -> QKĐ
27. in 
28. in ( in + tháng)

18. They aren't playing soccer at the moment.
19. His father asked him if he had played the piano the day before.
20. Does their teacher often tell them to learn new word?
21. Mai lives with her parents at 40 Tran Hung Dao street in the center of the city.
22. Who is your sister talking to at present?
23. Is talking to him interesting?
24. There is a refrigerator at the right corner of the room.
25. She is good at playing the guitar.
26. He prefers reading books to watching TV.
27. My mother let me go out every day.

28. He didn't make us do our homework yesterday.
29. She has more books than her friend.
30. I eat less meat than he does everyday.
31. She did fewer exercises than her friends yesterday.
32. Hoa drank much more water than him yesterday.