20. I should keep silent, _____?
A. shouldn't I

21. He mightn't get there in time, _____?
B. may he.

22. Everything is fine, _____?
 B. isn't it

23. I wish to study English, _____?
A. don't I

24. What a nice dress, _____?
C. doesn't it

25. One can be one's master, _____?
A. can't you

26. You'd better stay at home, _____?
C. don't you

27. You'd rather learn English, _____?
   Answer: A. hadn't you

28. You don't believe Peter can do it, _____?
D. don't you

29. These are 3 oranges you bought yesterday, _____?
C. are these

30. He seldom helps her, _____?
A. doesn't he