15. It's our duty to study harder and harder.
⇒ Our duty is studied harder and harder.
16. It's hard to study Chinese.
⇒ Chinese is hard to study.
17. Don't let him visit her.
⇒ He is not let to visit her.
18. Don't let your children help you.
⇒ Yor children isn't let to help you.
19. People consider that he is famous scientist
⇒ He is considered that he is a famous scientist.
20. My brother saw a thief go into the shop.
⇒ A thief was seen go into the shop.
21. You need to finish your homework.
⇒ Your homework need to be fineshed.
22. He should see his girlfriend weekly.
⇒ His girlfriend should be seen weekly.
23. Hoa can't have bought a new car.
⇒ A new car can't have be bought by Hoa.
24. Trang should have visited her aunt yesterday.
⇒ Trang's aunt should have be visited yesterday.
25. I am having my brother explain this exercise now.
⇒ My brother is being having explained this exercise now.
26. Peter usually gets his father to repair his motorbike.
⇒ Peter's father usually gets to be repaired his motorbike.
27. Her mother made her explain why she had been late last night.
⇒ She was made explain why she had been late last night.
28. The teacher usually watches his students do the test.
⇒ His students are usually watched do the test by the teacher.
29. Turn off the TV at once.
⇒ TV should be turned off at once.
