Unit5DiscoveringUsefulStructuresModalverbs导学案--人教版高中英语必修第三册.docx

Unit 5 Discovering Useful StructuresModal verbs> DefinitionA modal verb is a type of verb that is used to indicate modality - that is, likelihood, ability, permission, and obligation.Some commonly used modal verbs: can, could, may, might, must, ought to, shall, should, will, would...> Grammatical Features令 在形式上，情态动词没有实义动词的各种变化，只有could, would, had to, might 等几个过去式，其他情态动词如must, ought to等的过去式皆与现在式同形令 在意义上，大多数情态动词有多个意义，如can可以表达“能力”“可能”“许 可”等令在用法上，情态动词须后接，构成谓语动词无和 OFunctionsnecessity possibility obligationrequestadviceintention > can / couldnecessity possibility obligationrequestadviceintention > can / could• You'd better not open it.• What would you do if you were in her situation?• It may seem lucky to you.• May we ask what you're doing in this country?• Astronauts must wear spacesutte when they work In space because...• You have to read between the Unes becausethe real messages are often hidden...1 .表示，相当于be able to,常译为“会，能”。

can表示, could表示令 He can ride a bike now, but he couldn't a few weeks ago.2 .表示二 o can多用手和 中，但也可用在肯定句中；could表示过去的可能，多用于 中 That can't be Mary - she has gone to school.令 I told the boss that I couldn/t finish the work in such a short time.3 .表示请求或允许，译为“可以”表示此意时，用could语气更委婉令 -Can/Could I borrow your bike? - Sure.> may / might1 .表示 o might比may语气更委婉用“May征询对方许可时比拟正式和客气，而用“Can I…？”在口语中更常见令 -May I open the window? - Certainly.令注意：答语防止使用may,以免显得太严肃或太不客气2 . may用于祈使句,表示令 Moy you succeed!令 May you have a good journey!3 .固定搭配:may/might as well表示“还是为好，不妨”令 You may as we// stay longer.> must / have tomust表示“:在回答以must开头的一般疑问句时，如果是否 定HI答，不能用mustn't （禁止，不准）,而应用 或（不必）。

令 一Must we hand in our exercise books today?0 —Yes, you must. / No, you don't have to. / No, you needn't.1. must是说话人的主观看法，而have to那么强调客观需要今 The play isn't interesting. I really must go now.令 I had to work when I was your age.shall, should / ought to1. shall用于第一、三人称的疑问句中，表示 o令 What shall we do this evening?2. shall后还二、三人称，表示说话人给对方的、、允诺、 威胁或决心令 You shall fail if you don't work hard.3. shal由T用于正式文件、法律、规章制度等，表示 o令 The president shall hold office for five years.4. should常与亚扁工0亚、\/^等词连用,表示意外、惊讶等情绪,意为'" 令 I don't know why you should think that I did it.5. should与ought to表示，意为“应该"也可以表示可能性，意思 相当于 will probablyo令 We should/ouqht to all work together to draw a new and better blueprint for the sake of succeeding generations.will, would / used to1. will> would 表示 等,would 语气更。

令 Will/Would you pass me the ball, please?2. will、would可表示意愿令 He yvil[ donate money to the poor although he is not wealthy.3. will五可表示“"，表示一般规律或真理令 Fish yvil[ die without water.4. would表示过去 的动作或某种倾向令 During the vacation, he would visit me every other day.5. used to表示,现在不再这样令 He used to be late, but now he is the first one to arrive at school every day.dare / need1 . dare和need作为情态动词时,常用于 句和 句中令 Need I tell her the news at once?令 He dare not go to school alone.2 .这乔词也可以用作 动词令 Jack needs to help her because she is in trouble.令 She didn/t dare to stay at home alone.had better / would ratherhad better "",缩写为"d better,否认为 had better not,表示提 出、等,含有“应该做某事，有义务做某事”之意，一般适用于对晚辈、平辈。

令 It,s half past two. We had better go home.1. would rather “,”缩写为?d rather,否认为 would rather not.令 He would rather starve than beg for food.情态动词表推测一Um>M That must Smith.doiwIto mfaht 8 homework.It must lbws rafaetf tart ntahL意:令可能性可分为 可能性和具体事情 可能性两种令客观的可能性并不表示具体某事是否会发生，而用来说明 O令 情态动词can可用于肯定句中表示 的（或理论的）可能性，而表示具体事情实际发生的可能性时,can 一般不用于肯定句如：令 Accidents cgn_ happen on such rainy days.在这样的赢天气里可能会发生事故客观的可能性）令 We m” go to the cinema tonight, but we are not sure yet.今晚我们可能去看电影,但还没确定实际可能性，不用can）表示具体事情实际发生的可能性的层次（由强及弱）比拟词解否认式京间式must必定,必然//should按说应该应该不会/ought to按说应该应该不会/can/小可能有可能吗？could微弱的可能不可能语气比C81扇may或许,也许,也说不定可能不/might比may还弱比may not还弱/ExamplesHe might be a thief.• That may be our taxi.• That cou/d be our new class building.• He ouqht tbshould be here on time.• He must/has to be the wanted man.> V 情+havedone令 情态动词原形+have done表示。

令情态动词过去式+have done还可以表示 意义试比拟：令 They may have just qraduated from university.令 They miqht have just qraduated from university.令 He cannot have forqotten it.令 He couldn't have forqotten it.ExercisesWith so much work on hand, you to see the game last night.A. mustn't goB. could have gone C. shouldn't goD.shouldn't have gone- I saw Mary in the library yesterday. - You her. She is still abroad.A. mustn't see B. can't have seen C. mustn't have seen D. couldn't seeAunt Mary the train; otherwise she would have arrived here by now.A. must have missed B. should have missed C. missedD. mightmiss1. Jim says we stay in his house as long as we leave it clean and tidy.A. mustB. canC. needD.shouldIn today/s information age, the loss of data cause serious problems for acompany.A. needB. shouldC. canD. mu。