情态动词can的用法.doc

情态动词can 的用法小结情态动词是高考的考点，对中学生来说也是个难点，而can的用法较其他情态动词多，现根据中学课本和近几年的高考试题，将其重点内容列出。一、表示能力1. Can you type?2. I can do it.can 与be able to 的区别 1. be able to 能用于各种时态。“设法做成某事”相当于 managed to do sth. / succeeded in doing sth. 2. can / could 只能表示现在或过去的能力。 例： 1) A computer _ think for itself, it must be told what to do. A. cant B. couldnt C. may not D. might not析：答案是A. 表示能力。2) The fire spread through the hotel very quickly, but everyone _ get out. A. had to B. would C. could D. was able to析：答案是D. 表示经过努力才成功地逃出大火。二、can/could 表示许可/允诺1Can/could Tom use the car?Yes, he can.与may /might 的区别1might, could 比较委婉， 一般多用于疑问句。 2在以could, might 表示征询对方意见或表示请求时，回答应相应使用can, may.例：1) Could I borrow your dictionary? Yes, of course you _. A. might B. will C. can D. should析：答案是C. 第一句的请求用could, 所以回答时相应用can.2) Might I watch TV after supper? Yes, you _. A. may B. must C. might D. can析：答案是A. 第一句的请求用might, 所以回答时相应用may.3) -Could I call you by your first name? -Yes, you _.A. will B. could C. may D. might析：答案是C. 第一句的请求用could, 回答时相应用can, 但选项中没有can,所以最佳的是may.三、can指可能性He cant be at home. He has gone to Beijing.与must may , might, could /Should, ought to的区别1.should, ought to: 按理应当，很可能2.must: 表示肯定的猜测3.may /might: 表示可能的猜测4.can/could: 表示否定或疑问的猜测例：1） -when can I come for the photo ? I need them tomorrow.- They _ be ready by 12:00A. can B .should C. might D. need析：答案是B. 根据情景，应表示可能的猜测，选might可能会走掉顾客。2) Peter _ come with us tonight, but he isnt very sure yet. A. must B. may C. can D. will析：答案是B. 根据he isnt very sure，表示可能的猜测。3) .Michael _ be a policeman, for he is much too short.A. neednt B. cant C. should D. may析：答案是B. 根据for he is much too short, 可以判断是表示否定的猜测。4) -_he be watching TV now?Yes, he _ be watching TV now.No, he _ be watching TV now.A.Must; can; mustntB. Can; must; cantC. Can; can; mustnt D. May; must; neednt析：答案是B. 第一句和第三句分别表示疑问和否定的猜测，第二句表示肯定的猜测。四、 can /could have done1. 过去有能力做到而实际上没有做到的事情，含有责备或劝告之意。2. 用于否定句，对过去发生事情的否定猜测。例：1) -There were already five people in the car, but they managed to take me as well. -It _a comfortable journey A. cant be B. shouldnt be C. mustnt have been D. couldnt have been 析： 答案是D. 根据上下文，已经有5个人在车上，但还是把我带上，所以，这次路途不可能是舒服的，属于否定的猜测。而第一句的时态用过去时，所以是对过去发生事情的否定猜测。2） You made a lot of mistakes in your composition yesterday. You _ it much better.A. can wr