1、在回答must开头的一般疑问句时,肯定回答用must,否定回答用needn't或don't have to.如: 1)—Must I finish my homework before eight o'clock? —Yes,you must. 2)—Must I attend the meeting? —No,you needn't(No,you don't have to).You can ask Tom to go instead. 2、在回答may开头的一般疑问句时,肯定回答用may,否定回答用mustn't.如: 1)—May I watch TV after supper? —Yes,you may./ No,you mustn't. 2)—May I stop here? —No,you mustn't. 3、在回答need开头的一般疑问句时,肯定回答用must,否定回答用needn't.如: 1)—Need we stay behind after school? —Yes,you must. 2)—Need he go now? —No,he needn't. must的反意疑问句 如果陈述部分含有表推测的情态动词must,其反问部分不能用情态动词, 应根据具体情况而定. A.must表示“应该”,其疑问部分用mustn't(不应该),如: You must work hard next term,mustn't you 下学期你应该努力学习,对吗? B.must表示“必须”,其疑问部分用needn't(不必),如: We must go at once,needn't we? 我们必须立刻走,是吗? C.must表示推测,其疑问部分必须与must 后面的主要动词相呼应.如: 1)对现在动作或存在的情况的推测: You must know the answer to the exercise,don't you? 你一定知道这项练习的答案,是不是? That must be your bed,isn't it?那一定是你的床,是吗? 2)对过去发生的动作或存在的情况的推测: ①表示肯定 You must have left your bag in the theatre,haven't you? 你一定是把包落在剧场了,是不是? Aunt Liu must have got to the U.S.A.yesterday,didn't she? 刘大婶昨天准是到了美国了,对不? ②表示否定 表示推测时,否定式通常不是must not,而是can't (cannot).如: He can't have been to your home; he doesn't know your address,does he? 他不可能去过你家;他不知道你的地址,是不是? D.陈述部分含情态动词mustn't,表示禁止时,附加疑问部分就可以用must或may,如: We mustn't be late,must we?(may we?) 我们不可以迟到,是吗? need 带情态动词need的反意疑问句,疑问部分常用 need +主语. We need not do it again,need we 当 need 为实义动词时,疑问部分用助动词do + 主语. She doesn't need to go home alone,does she? |
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