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1、Module 6 Book VIII The Tang Poems Grammar 外语教学与研究出版社 情态动词must, can, could, may, might表推测的用法： 情态动词中的must, can, could, may, might都表推测 。其中must的可能性最大，can / could次之，may / might最小。具体用法如下： 1. must的用法 （1）表示推测“可能性”时，意思是“一定、准是 ”，语气较肯定，较有把握。 He must be American. = It is certain that he is American. 他准是个美国人。 （2
2、）must表推测只能用于肯定句。 如表示“一定不、肯定不”的意思时，应用cant, 如询问某种可能时，应用can。 He must know my address. 他肯定知道我的地址。（ 一定） He cant know my address. 他肯定不知道我的地址。 （一定不） Can he know my address? 他知道我的地址吗？（询问 可能性） （3）must表示推测时，可以推测现在/正在发生的动 作/过去发生的动作。 He must have a car now. （现在）他一定有辆小汽 车。 He must be doing his exercises in the c
3、lassroom. （正在进行）他一定在教室里做练习。 He must have finished the work.（过去发生）他一 定已完成了工作。 注：must表示推测时很少用于将来的情况。一般不用 He must come tomorrow.可用Its certain / Im sure that he will come tomorrow. （4）在反意疑问句中，当附属部分含有表示推测意义的must 时，疑问部分的助动词应与must后面的动词在非推测情况下的 用法保持一致。 He must be a worker, isnt he? （现在）他准时个工人，是 吗？ You must
4、have learned English for many years, havent you? （完成时）你一定学了好多年英语，是吗？ 比较： It must have rained last night, didnt it? （过去）昨晚一定 下雨了，是不是？ He must have arrived by yesterday morning, hadnt he? 2. can / could的用法 （1）can表示推测“可能性”时，往往用于否定句或疑问句 。Cant“一定不”，can在疑问句中意思是“会、可能”。 He cant be at home. = It is impossibl
5、e that he is at home. 他一定不在家。 （2）can /cant+ have done，表示对过去发生的动作进行推 测。 He cant have gone to Shanghai for I saw him a minute ago. 他不可能去了上海，我刚才还看见他。 Its so late. Where can she have gone? 天晚了，她可能去 哪儿了呢？ （3）could 还可以用于表示客气、委婉、礼貌的请 求语气。 Excuse me, could you tell me the way to the bus station? Could you h
6、elp me? （4）could have done 本能做但未做，表虚拟语气 I could have done it well，but I wasnt so careful then . 3. may和might的用法 （1） may, might表示推测“可能性”时，意思是“ 可能”、“也许” He may / might be American. = It is possible that he is American. 他可能是个美国人。 注：might不表示过去时态，只是语气上比may更委婉 ，表示的可能性更小。 （2）may, might表推测时，可以用于否定句，意思是 “可能不
7、、也许不”，但不用于疑问句。 He may / might not be at home. 他也许不在家。 （3）may, might可以推测现在正在发生的动作或过 去发生的动作。 He may / might be sleeping now. The boy may / might not be watching TV at home. 这个男孩可能没在家看电视 These students may / might have seen the film before.（过去） 这些学生以前可能看过这部电影。 u Choose the best answers : 1. I thought y
8、ou_ like something to read. So I have brought you some books. A. ought B. might C. would D. must 2. That man must be Sarahs husband. -No, he_ be her husband. She is still single. A. cant B. mustnt C. may not D. ought to 3. Peter _come with us tonight, but he isnt very sure. A. must B. may C. can D.
9、will 4. What_ it be? -It_ be a mail box, for it is moving. It_ be a car. A. can; cant; must B. can; can; must C. can; mustnt; must D. must; mustnt; can 5. Look, someone is coming. Guess_ . -Jack. Hes always on time. A. who can it be B. who he may C. who he can be D. who it can be 6. I saw Mary in th
10、e library yesterday. -You_ her. She is still abroad. A. mustnt see B. cant have seen C. mustnt have seen D. couldnt see 7. David, you _play with the valuable bottle, you_ break it. A. wont; cant B. mustnt; may C. shouldnt; must D. cant; shouldnt 8. Susan refuses to marry Jack now. She _her mind. A.
11、must change B. should have changed C. must have changed D. would have changed 9. Sue_ come together with us tonight, but she isnt very sure yet. A. must B. may C. need D. will 10. Aunt Margaret_ the train, otherwise she would have arrived here by now. A. must have missed B. should have missed C. had
12、 missed D. might miss 情态动词+have+done” 表“本来” 使用情形分析 一、should have done过去本来应该 （而实际上并没有) should not have done 本不应该 而实际上却已经 ” 如：1、We should have studied last night, but we went to the concert instead . 我们昨晚本应学习的，但我们 却去看音乐会了。（实际上没有学习） 二、could have done 它表示“过去本来能够“ 实际上没能做。如 1、I could have run 100 metres i
13、n 12 seconds. 我本来能用12秒钟完100米的.（实际上没能） 2、If you could have finished the task in time， you could have been promoted. 如果你当时能如期完成那任务的话，你可能已 提升了（实际上没有被提升） 三、need not have done 它表示过去已做的事，事实上没有必要。如， 1、I need not have got up so early . 我本来不必要那么早起床的（事实上早已起床） 2、I need not have waited for the train for an hour
14、. 我本来不必要等一个小时的火车。 （事实上已经等了一个小时） 问题: would have done 在什么情况下使用呢? 四、would have done 用在虚拟语气中 表示与过去事实相反之假设的结果，常与if 的条件 句连用。 1、 I would have helped you if I had known of your difficulties . 要是我当时知道你们的窘境，我就会帮 助你了（而实际上没有帮助你） 2、If it hadnt rained yesterday, we would have gone out for a walk .假如昨天没下雨，我们就去散步了。
15、 （实际上没有去）。 Practice 1.Mr White _ at 8:30 for the meeting, but he didnt turn up. A. should have arrived B. should arrive C. should have had arrived D. should be arriving 2. If he had been here yesterday, he _ this pop star. A. would meet B. would have met C. met D. must have met 3.It is hard for me to imagine what I would be doing today if I_ in love at the age of seven with the Melinda Cox Library in my hometown. A. wouldnt have fallen B. had not fallen C. should fall D. were to fall