必修情态动词.doc

【本讲教育信息】一. 教学内容：情态动词may/might, can / could, will/would, shall/ should, must/ cant 二. 知识精讲：（一）can/ could 1. 表示能力He can speak several languages. 他会讲好几种语言。Lucy could play the piano at the age of three. 露西三岁时就会弹钢琴。知识拓展：1）因为can不能和其他助动词连用，所以表示将来时常用will be able to.You will be able to skate after you have practiced it two or three times.你练习两三次后就会溜冰了。2）辨析：could与was/were able to两者都可表示“过去一般的能力”。例：My father could /was able to speak five languages.我父亲以前会说5种语言。如果表示“过去某一具体的能力”，也就是在过去某一特定场合做成了某事的能力，就不能用could，只能用was/were able to。例：I talked for a long time, and in the end I was able to make her believe me. 我说了老半天，最后才使她相信了我的话。Below the 11th floor people were able to escape from the fire.11层楼以下的人逃脱了火灾。could的否定形式couldnt无此种限制，也可用来表示过去某个特定场合做某事的能力。例：Simon was so drunk that he couldnt find the front door.西蒙喝得烂醉，竟找不到正门在哪里。2表可能性can表“可能性”时可用于肯定句、疑问句和否定句。这时cant与must相对表示语气最强的否定推测。She lives in Paris but she speaks with a German accent. She cant be French. She must be German.她住在巴黎，但她说话带德国口音。她不可能是法国人，一定是德国人。注意：can在肯定句中表“可能性”时是表示“理论上的可能性”，而不是表示具体某事发生的可能性。Accidents can happen.意外情况是可能发生的。Scotland can be very warm in September.九月的苏格兰可能非常暖和。3表示请求和允许Can I have a look at your new book?我可以看一下你的新书吗？Could I use your computer? 我可以用一下你的电脑吗？Yes, you can. 是的，可以。4表示惊讶、怀疑、不相信的态度。常用于疑问句和否定句。 What can he be doing at this time of night？这么晚了，他究竟在干什么呢？How can you believe such a liar like him?你怎能相信他那样的骗子呢？（二）may / might 1. 表示请求和许可May I trouble you to pass me the book?能不能麻烦你把那本书递给我？Might I point out your mistakes? 我可不可以指出你的错误。Yes, you may （can ）.可以。/ No, you mustnt (cant ). 不可以。2. 表示可能性 may/might表示“可能性”时只用于肯定句和否定句，疑问句中通常用can表示可能性。He may be very busy now.现在他可能很忙。It may not be true.这可能不是真的。Can it be true? 这可能是真的吗？3. 表示祝愿常用于May + 主语+动词原形结构。May you succeed. 祝你成功！4. 构成固定搭配 may / might as well意为“不妨；还是的好。”You may/might as well stay where you are.你还是待在原地好。If that is the case, we may/might as well try.如果那样的话，我们不妨一试。（三）will/ would 1. 表示意志、决心或愿望。If you will do the work, you must do it well.如果你愿意做这份工作， 一定要做好它。Surely we will support all the people in the world in their struggle for peace.我们一定要支持全世界人民争取和平的斗争。2. 表示经常性、习惯性动作，意为“常常”。He will sit there hour after hour looking at the traffic go by.他会经常一连几个小时坐在那儿观看来往的车辆。We would sit around grandpa after supper, listening to his stories. 过去，晚饭后我们总会围在爷爷身边， 听他讲故事。3. 表示对对方的请求,用于第二人称作主语的疑问句中，would的语气比will委婉。Would/ Will you kindly tell me the way to the station? 请问到火车站怎么走？4. 表示预测或猜测。That man will be the doctor we are after.那个人大概就是我们要找的医生。It would be about six when he left school.他可能是六点左右离开学校的。5. 表示事物的某种性质或倾向。Boys will be boys.孩子就是孩子。People will die without air or water.离开水或空气，人就会死。（四）shall/should1shall 的用法1）表示征求对方意见或向对方请示 ，常用于第一、第三人称的疑问句中。Mrs Johnson has arrived. Shall she come upstairs or will you go downstairs to meet her?约翰逊夫人到了。是请她上楼来，还是您下去见她呢？Shall he finish the work today?他今天就得完成工作吗？2）表示命令、规定、警告、允诺或威胁等， 常用于第二、第三人称的陈述句中。You shall come to my office immediately. 你必须马上来我的办公室。You shall get an answer from me by tomorrow. 到明天你就会得到我的答复。Each competitor shall wear a number.每个参赛者都要佩戴一个数字牌。2. should 的用法1）表示劝告和建议，意为“应该”。We should master a foreign language at least.我们应当至少掌握一门外语。You should go and see Mary sometime next week.你下周应该找个时间去看看玛丽。2）表示对某种情况的推测、估计。They should /ought to be there by now, I think.我想他们现在应该已经到那儿了。This book should be out in a month or so.再有个把月这本书应当会出版了。3）表示说话人惊讶、失望、恼怒和生气等情绪。I am sorry that she should be so careless. 我感到遗憾她竟会那样粗心。It seems so unfair that this should happen to me.这事竟发生在我身上，这似乎太不公平了。4）用于固定句型在It is natural (strange, necessary, surprised, impossible, important ) that“句型，由lest（以免）、for fear (that) (以防)、in case（以防万一）引导的从句中以及有advise, suggest, order, demand, request 等动词的从句中，谓语动词要用“should +动词原形”表示“理所当然”、“奇怪”、“必要”、“惊异”等意思。It is necessary that he (should) be sent there at once.有必要马上派他到那里去。It is strange that he should say so. 他会说这样的话真是奇怪。I advised that he (should) start at once.我建议他立即动身。Let us go at once lest we should be late for the train.我们马上走吧，以免赶不上火车。（五）must / cant must的用法1. 表示“必须，应该，命令，禁止”，语气较强烈。We must do everything step by step .我们必须按部就班地做一切事情。You must cut down on your smoking.你必须少吸烟。Drivers mustnt drive after drinking.司机严禁酒后驾车。You mustnt leave your books about.你不能把书扔得到处都是。2. 表示对过去、现在、将来的推测，意为“一定，准是”，只用于肯定句中，表示否定的推测用cant，表示疑问的推测用can。You have worked hard all day. You must be tired.你辛苦干了一整天，一定累了。He must be working in his office. 他一定在办公室工作呢。I didnt hear the phone. I must have been asleep.我刚才没有听到电话响，我一定是睡着了。If Tom didnt leave here until five oclock, he cant be home yet.如果汤姆五点才离开这儿，他此时一定还未到家。Someone is knocking at the door. Who can it be?有人在敲门，会是谁呢？3. must可表示某种与说话人的意愿相反、不受欢迎的事情，意思是“偏偏”、“偏巧”。Why must it rain on Sunday?为什么偏偏星期天下雨？Why must you always bother me? 为什么你偏要打扰我呢？注意：在回答must的问句时，否定回答用neednt或dont have to ，表示“不必”，而不用mustnt。Must I come back before ten? 我必须十点以前回来吗？-Yes, you must .是的， 你必须十点前回来。-No, you neednt / dont have to. 不，不必。cant 的用法1表示“不能，不会”，也可表示“条件不允许”。We cant swim here on account of the sharks.我们不能在这儿游泳，因为有鲨鱼。2可表推测语气。That person cant be our teacher. 那个人不可能是我们的老师。即学即用1. You cant imagine that a well behaved gentleman _ be so rude to a lady. A. might B. need C. should D. would 2. Mr. Bush is on time for everything. How _ it be that he was late for the opening ceremony ?A. can B. should C. may D. must 3. I hear youve got a set of valuable Australian coins. _ I have a look ? Yes, certainly. A. Do B. May C. Will D. Should 4. Is John coming by train ? He should, but he _ not. He likes driving his car. A. must B. can C. need D. may 5. Naturally, after I told her what to do, my daughter _ go and do the opposite !A. may B. can C. must D. should 6. Tom, you _ leave all your clothes on the floor like this !A. wouldnt B. mustnt C. neednt D. may not 7. There _ be any difficulty about passing the road test since you have practiced a lot in the driving school. A. mustnt B. shant C. shouldnt D. neednt 8. Could I borrow your dictionary?Yes, of course, you_.A. might B. will C. can D. should9. I often see lights in that empty house. Do you think I _ report it to the police?A. should B. may C. will D. can 10. Excuse me, but I want to use your computer to type a report. You _ have my computer if you dont take care of it. A. shant B. might not C. neednt D. shouldnt 11. Children under 12 years of age in that country _ be under adult supervision when in a public library. A. must B. may C. can D. need 12. Isnt that Anns husband over there ? No, it _ be him Im sure he doesnt wear glasses. A. cant B. must not C. wont D. may not 13. How _ you say that you really understand the whole story if you have covered only part of the article ?A. can B. must C. need D. may 14. The fire spread through the hotel very quickly but everyone _ get out. A. had to B. would C. could D. was able to15. Theres nothing on television. We_ as well go out tonight. A. will B. shall C. should D. may答案：CABDC BCCAA AAADD 【典型例题】1. It is usually warm in my hometown in March, but it _ be rather cold sometime. A. must B. can C. should D. would2. Liza _ will not want to go on the trip she hates traveling.A. will B. can C. must D. may3. You _ be hungry already you had lunch only two hours ago!A. wouldnt B. cant C. mustnt D. neednt4. John promised his doctor he _ not smoke, and he has smoked ever since. A. might B. should C. could D. would5. According to the air traffic rules, you _ switch off your mobile phone before boarding.A. mayB. canC. wouldD. should6. Some people who don