2010届高三英语情态动词课件

情态动词,By Laura,The basic uses of Modal Verbs,可兼做行为动词的情态动词：need 、 dare,情态动词 (+动词原形),行为动词,.,need,dare,1.无人称和数的变化;,2.尤其用于：,*否定句及疑问句中;,*在if/whether之后;,*或与hardly, never, no one, nobody连用;,3.常以neednt 和darent 的形式出现;,4.dare有其过去时dared.,多用于肯定句; (sb.) need to do dare to do(sth.) need to be done (sth.) need doing,1. Can,Could 过去式；语气更委婉,Can 表示习惯能力， 而be able to表示经过那里而做成了某事。2. 在否定结构中，二者可以互换。,1.在否定、疑问句中表示“对过去发生行为 的可能性猜测。2. 在肯定句中表示“本来可以做而未做”,The door was lacked. She couldnt have been at home.You could have been more careful.,1. May,Might 过去式；语气更委婉,1.在否定、肯定句中表示对过去动作的推测 “也许是”2. Might+have+p.p表示虚拟，表“劝告、责备之意。”,Eg. 1. She may be still waiting for us. 2. May I come in? 3.May you have a happy holiday.,Eg. 1. He might have spoken to her yesterday. 2. You might have told me earlier.,1. Must,表示肯定的猜测,但只用于肯定句，而mustnt 表示“禁止、不准”,Must表示主观Have to表示客观需求Have got to 多见于口语,3. must + have +p.p,对过去事情的肯定猜测。,Eg. The road id wet. It must have rained last night.,1、Shall /should,2、shall/should + have +p.p ought to,表示本应该做而未做。,should 过去式 语气更委婉,Eg. You should have been five minutes ago.,Will/ would,1、Would 后只能接表示动作的动词。,2、used to 则还可以接表示状态的动词。Eg. He used to be a worker.,补充说明,1.、情态动词的过去式与原形相比，多点礼貌，少点冒昧， 语气更为委婉。,情态动词在一般疑问句中的回答： Can you sing? May I come in? Must I handin the book now? Need I finish it now?,表示推测情态动词的重要用法.,肯定的推测可能的推测否定的推测疑问的推测,must/should,对将来 对现在 对过去,情态动词,may, might,cant, couldnt,can, could,+ V. + V. + have done常见must be + be doing,+ V. + V. + have done + be doing 可以用not表示“可能不”,+V. + V. + have done + be doing,+ V. + V. + have done + be doing,Choose the best answers :1. I thought you_ 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 to3. Peter _come with us tonight, but he isnt very sure.A. must B. may C. can D. 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; mustC. can; mustnt; must D. must; mustnt; can5. Look, someone is coming. Guess_ .-Jack. Hes always on time.A. who can it be B. who he mayC. who he can be D. who it can be,6. I saw Mary in the library yesterday.-You_ her. She is still abroad.A. mustnt see B. cant have seen C. mustnt have seen D. couldnt see7. David, you _play with the valuable bottle, you_ break it.A. wont; cant B. mustnt; mayC. shouldnt; must D. cant; shouldnt,8. Susan refuses to marry Jack now. She _her mind.A. must change B. should have changedC. 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 missedC. had missed D. might miss,典型错误,1. He mustnt be in the classroom. ( ),Cant,2. You might leave the bag on the bag. ( ),might have left,3. You must have seen the film last week, havet you? ( ),didnt you,4. Li ming must have been to Japan, didnt he? ( ),hasnt he,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 in 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. 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。（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 metC. met D. must have met