--No, you ______.
A. needn't B. mustn't C. don't D. may not
2. -Who is the man over there? Is it Mr Li?
--No, it ______ be him. Mr Li has gone to America.
A. mustn't B. may not C. can't D. needn't
3. To make our city more beautiful, rubbish ______ into the river.
A. needn't be thrown B. mustn't be thrown
C. can't throw D. mustn’t throw
4. -Must we hand in the papers now?
--No, you ______.
A. can't B. may not C. mustn't D. needn't
5. You_____ to the meeting this afternoon if you have something important to do.
A. needn’t to come B. don’t need come
C. don’t need coming D. needn’t come
6. You’d better _____late again.
A. don‘t B. not be C. not being D. won’t be
7. You _______ smoke in the hospital.
A. needn’t B. oughtn’t to C. ought to not D. may not
答案与解析：
1. A.用must来提问，肯定回答用Yes, you must;否定回答用No, you needn’t 或No , you don’t have to, 故选A.
2. C. 完全否定的猜测用can’t,;“mustn’t”表“ 禁止、不许”，不用在否定猜测中，排除; “may not” 表“可能不是”，用在不确定猜测中，但根据“Mr Li has gone to America.”可知 may not不符合句意，排除;“needn’t”表“不需要”，不符合句意，排除。
3. B.rubbish与throw之间存在被动关系，用被动语态，排除C、D;其次，往河里扔垃圾这个行为是禁止、不许的，而不是不需要，排除A。
4. D. 用must来提问，肯定回答用Yes, you must;否定回答用No, you needn’t 或No, you don’t have to, 故选D。
5. D.need和dare既可以当情态动词，又可以当实义动词。当情态动词时，need/dare 后接动词原形，无人称和数的变化，否定句直接在后面加not;当实义动词时，need/dare 后接不定式，有人称和数的变化，且否定要用助动词。A项的needn’t，not家在need后面，所以need是情态动词，后应接动词原形，排除;B项的need前有助动词don’t, need是实义动词，后应接不定式，排除;C项need前也有助动词，need为实义动词，后应接不定式，排除C。
6. B.had better最好做某事，后接动词原形，其否定形式直接在better后面加not, had better not最好别做某事，且not 后接动词原形。
7. B.ought to ,应该做某事，其否定形式为 ought not to，缩写为oughtn’t to，排除C;对在医院吸烟这个态度应该是“不应该”，而不是“不需要”或“可不”，排除A、D。
