20. She began studying Japanese for 5 years.

III. 
2. She noticed the boy ran away from the house.

3. I overheard he said he didn't want to learn Math.

4. The policeman made the thief to empty his pockets. 

5. I heard he leave the house early this morning.

6. She stood there and watched him drive away.

7. I could feel that the robber came from the back door.
IV.

1. I saw them playing football.

2. Jasey didn't make her children to go out in the evening.

3. My mother let us finish our exercises before going to bed.

4. Would you like a cup of coffee?

5. We want to play football with our friends at weekends.

6. He noticed they went out of the restaurant.

7. I felt the animal mived on my hand.

8. They have never seen a big tiger before.

9. It is very exciting to read his books.

10. To speak to him is easily.

11. We want to play football with our close friends at weekends.

12. It is very nice to meet your parents.

13. All of us felt that the house shook violently.

14. His injured knee made him couldn't play well in the last match.

15. The women noticed the animals moved toward me.

16. The customs officer made him to open the briefcase.

17. My parents make me to have breakfast at home.

18. I want you to travel by bus.

19. It is difficult for her to meer others at social events.

20. The teacher doesn't allow to eat in the classroom.

21. I was made stay there for three weeks.

22. The last time I talked to him was on his 15th birthday.

23. People find traveling by air the most expensive.

24. It's five years since Mary started to learn Vietnamese.

V.

1. C. stay

2. B. not to go out