must-may-can的反义疑问句.docx

当陈述部分含有情态动词must, may, can’t, 且表示推测时，反意疑问部分不能用must, may, can’t自身，应和后面的实义动词保持一致，随时间和人称而变化，如何才能快速准确地做出判断呢？根据笔者多年的教学经验，利用还原法解决这一问题较好。 所谓还原法，就是先把句子还原成一个不带must推测意味的句子。如He must be a teacher.可还原为He is a teacher.其反意疑问句为isn’t he? 也就是原句的正确答案。 同样方法You must have waited for a long time.可还原为 You have waited for a long time.其反意疑问句haven’t you? 即原句的答案。 注意：1、在must 表示现在情况的推测时，要注意主语对还原后句子谓语动词的影响。如： 1. He must be ill at home, isn’t he? （还原为He is ill at home.） 2. They must be ill at home, aren’t they? (还原为They are ill at home.) 2、must 表示对过去的情况推测时，要注意句意和时间状语对还原后句子时态的影响。如含有 for a long time, so far, before, since 等时间状语的句子还原后句子为完成时；而含有last night, yesterday, the other day, ten years ago 等时间状语的句子则还原为过去时。如： He must have seen her in the street yesterday, didn’t he? （还原为：He saw her in the street yesterday.） He must have learned English for more than 10 years, hasn’t he? （还原为：He has learned English for more than 10 years.）? ◆ must/ may/ can’t + do 表示对现在情况的推测，反意疑问部分用一般现在时。如： ① He must be Mr. Chen, isn’t he? 　　(相当于：I think he is Mr. Chen.)　他一定是陈先生，是吗？ ② He can’t be Mr. Chen, is he? 　　（相当于I don’t think he is Mr. Chen.）　他不可能是陈先生，是吗？ ③ He must be very tired, isn’t he? 　　(相当于：I believe he is very tired.)　他一定很累，是吗？ ④ Your mother may be at home, isn’t she? 　　(相当于：Maybe your mother is at home.)可能你母亲在家呢，是吗？ ◆ must/ may/ can’t + have done +过去时间状语，表示对过去情况的推测，反意疑问部分常用一般过去时。如： ① He must have stayed at home yesterday, didn’t he? 　　(相当于: I think he stayed at home yesterday.)他昨天一定呆在家里了，是吗？ ② You must have seen the film last week, didn’t you? 　　(相当于：I think you saw the film last week.) 你上周一定看这部影片了，是吗？ ③ It can’t have snowed last week, did it? 　　(相当于：I don’t think it snowed last week.)上周不可能下雪了，是吗？ ④ He may have gone home last night, didn’t he? 　　(相当于：Maybe he went home last night.)他可能昨晚回家了，是吗？ ◆ must/ may/ can’t + have done , 反意疑问部分常用现在完成时。 ① You must have met him before, haven’t you? 　　（相当于：I think you have met him before.）　你从前一定见过他，是吗？ ② You may have been to Tibet, haven’t you? 　　(相当于：Maybe you have been to Tibet.)