表示推测情态动词的用法.doc

表示推测情态动词的用法表示推测情态动词的用法 一、用法归纳1. 表示推测的情态动词有must, can, could, may, might等，且语气由左向右依次减弱。could, might并不一定是can, may的过去式，有时只是语气分别比can, may更弱。2. must (一定会，准会) 只用于肯定句；can (可能)一般用于疑问句或否定句；may (也许) 用于肯定句或否定句。虽然must和may均可用于肯定句，但在语气上must比may强得多，must表示有把握的肯定推测，而may表示没有把握的肯定推测。虽然can和may均可用于否定句，但在语气上cant(不可能)比may not(可能不)要强得多，cant是表示有把握的否定推测，而may not是表示没有把握的否定推测。could, might可用于肯定句、否定句或疑问句中，其区别在于语气上强弱的区分。3. should, ought to (按理应当), would, will,(很可能)等也可表示推测，语气都较肯定，且由左至右依次增强，但较must稍弱。4. 关于表示推测的情态动词后面所接动词形式，有下列三种情况：若对此刻正在发生的事，接“be +现在分词”；若对现在或未来情况的推测，接动词原形；若对过去情况的推测，接“have +过去分词”。二、实例分析Excuse me. Is this the right way to the Summer Palace?Sorry, I am not sure. It _ be. (湖北卷)A. mightB. willC. must D. can【分析】答案选A。由I am not sure(我没有把握)可知，后文是没有把握的肯定推测，用might。You might just as well tell the manufacturer that male customers _ not like the design of the furniture. (上海卷)A. mustB. shall C. mayD. need 【分析】答案选C。. may not意为“可能不”。句意是：你不妨告诉厂商男顾客可能不喜欢这种家具的花样。Isnt that Anns husband over there? No, it _ be himIm sure he doesnt wear glasses. (全国卷)A. cant B. must not C. wontD. may not【分析】答案选A。由No和后文Im sure可知，是有把握的否定推测，所以用cant (不可能)。When can I come for the photos? I need them tomorrow afternoon. They _ be ready by 12:00. (全国卷)A. can B. shouldC. might D. need【分析】答案选B。should表示“按理应当，大概”。用might语气太不肯定，顾客可能走掉。I have lost one of my gloves. I _ somewhere. (北京春)A. must dropB. must have droppedC. must be dropping D. must have been dropped【分析】答案选B。对已经发生的事进行推测用“must have +过去分词”，答案D是被动式，应排除。I stayed at a hotel while in New York. Oh, did you? You _ with Barbara. (全国卷)A. could have stayedB. could stayC. would stayD. must have stayed 【分析】答案选A。表示对过去情况的推测：“你可能和Barbara住在一起了”；must语气太肯定，与前面具有疑问语气的Oh, did you?不符。There were already five people in the car but they managed to take me as well. It _ a comfortable journey. (全国卷)A. cant beB. shouldnt beC. mustnt have beenD. couldnt have been【分析】答案选D。既然小汽车上“已有五人”，且是“设法”才把你带去的，如此拥挤，旅途当然“不可能”舒服。Tom graduated from college at a very young age. Oh, he _ have been a very smart boy then. (全国III)A. couldB. shouldC. mightD. must【分析】答案选D。由上文可知，应是有把握的肯定推测，用must(一定)。You _ be tiredyouve only been working for an hour. (四川卷)A. must notB. wontC. cantD. may not【分析】答案选C。由后文“你才只工作了一个小时”推断，“你不可能就累了”。表示有把握的否定推测，用cant。must not不允许；may not可能不。Its nearly seven oclock. Jack _ be here at any moment. (全国卷)A. must B. needC. shouldD. can【分析】答案选C。nearly暗示“时间不早了”，“按理应当(should)”Jack“随时(at any moment)”都有可能到达这里。must又语气过强；can一般不用于肯定推测；need意义不通，也不用于肯定句。I didnt hear the phone. I _ asleep. (全国卷)A. must be B. must have beenC. should beD. should have been【分析】答案选B。当时我没不听到电话铃响，那“一定是己经睡着了。Is John coming by train?He should, but he _ not. He likes driving his car. (全国卷)A. mustB. canC. needD. may【分析】答案选D。由“他自己喜欢开车”这一习惯推断，“他可能不会(may not)坐火车来”。can not“不可能”，语气太肯定。(from )Peter _ come with us tonight, but he isnt very sure yet. (全国卷)A. must B. canC. mayD. will【分析】答案选C。由but he isnt very sure. (但他没有把握)可知，Peter晚上来的可能性是不大的。表示没有把握的肯定推测用may(也许)。Are you coming to Jeffs party?Im not sure. I _ go to the concert instead. (全国卷)A. mustB. wouldC. should D. might【分析】答案选D。由Im not sure可知，