17. (Em làm đúng rồi)
18. Lan and Hoa have been helped by Nam
19. He has been helped by Nam
20. Lan can be helped by Nam
21. Lan and Hoa will be help by Nam
22. We should be helped by Nam
23. They must be helped by Nam
24. You used to be helped by Nam
25. Lan has to be helped by Nam
26. The children have to be helped by Nam
27. Lan is going to be helped by Nam
28. The other people are going to be helped by Nam
29. Lan is helped with her homework by Nam everyday.
30. Lan was met at the airport by Nam last Saturday
31. Lan will be met at the airport by Nam tomorrow
32. Lan has been helped with her homework by Nam since 2 o'clock