A. don’t smoke B. doesn’t smoke C. didn’t smoke D. not smoke

23. You shouldn’t have left the door open. Suppose a burglar _________ into the house.

A. had broken B. broke C. break D. breaks

24.If everything goes according to the plan， I _________ back before dark..

A. am B. shall be C. should be D. be

25. Suppose he never _________， what would we do?

A. came B. come C. comes D. coming

26. If you had taken the medicine， you ________ well now.

A. are B. were C. would be D. would have been

27. Had it not been for the free tickets， I ________ to the films so often.

A. didn’t go B. would not have gone C. haven’t gone D. not go

28. If you ________ hard at English， Your English would be good now.

A. work B. worked C. works D. had worked

29. I’m not tired enough to go to bed. I _______ if I went to bed now.

A. wouldn’t sleep B. would sleep C. would not have slept D. would have slept

30. My idea is that every student ________ himself of these rules.

A. informs B. informed C. should inform D. informing