2. You ____ leave a tip if you don’t want to.

A mustn’t　　 B don’t have to　　 C shouldn’t　　　 D can’t

1. One thing I don’t like about my school is that we students ____ wear a uniform.

A can　　 B have to　　 C need　　 D may

26. I have lost one of my gloves. I ________ it somewhere.　 (05北京春季)

　A. must drop　　　　 B. must have dropped

　C. must be dropping　　 D. must have been dropped

25. --- The woman biologist stayed in Africa studying wild animals for 13 years before she returned.

--- Oh, dear! She _______ a lot of difficulties! (05江苏卷)

A. may go through　　　　　　　　　　　 B. might go through

C. ought to have gone through　　　　　　 D. must have gone through

24. This cake is very sweet. You __________ a lot of sugar in it. (05辽宁卷)

　　　 A．should put B．could have put　 C．might put　 D．must have put

23. I _______have been more than six years old when the accident happened. (05天津卷)　　 A. shouldn't　　 B. couldn't　　　 C. mustn't　 D. needn't

22. Tom, you 　　　　leave all your clothes on the floor like this! (05全国卷1)　　 A．wouldn’t 　　　 B．mustn’t 　　　 C．needn’t D．may not

21. John, look at the time. _______ you play the piano at such a late hour? (05全国卷3)　 A．Must B．Can　 C．May　 D．Need

20. - Tom is never late for work. Why is he absent today?

　　　 - Something ________ to him. (05江西卷)

　　　 A．must happen　　　　　 B．should have happened　　　

　　　 C．could have happened　　　 D．must have happened

19. --- Lucy doesn’t mind lending you her dictionary.

--- She ______ . I've already borrowed one. (05湖南卷)

　　　 A. can't　　　 B. mustn't　 C. needn't　　 　　　 D. shouldn't