语法专项复习情态动词ModalVerb.ppt

语法专项复习： 情态动词 (Modal Verbs),常用的情态动词,can （could） may（might） shall（should） will （would） must（must） dare （dared） need （need）,have to ought to be able to used to had better,(1) 表示能力: can / could 只能表示现在或过去的能力。 *be able to 能用于各种时态。 *was / were able to : “设法做成某事” 相当于 managed to do sth. succeeded in doing sth.。,1. can ( could),(2)表允许，征求意见 Can/ Could I use your phone? *could语气上比can更委婉,客气。,can ( could),(3)表猜测，一般用于否定句和疑问句中： He cant be in the library now. Can it be Mr. Green?,can ( could),(4)表某人或某物一时的特点，表示“有可能， 有时会”。 Children can be naughty. It can be very warm in this area.,can ( could),You cant praise him too much. You cannot be over careful.,cannot cant 与tooover等词连用，意思是 “越越”,“无论怎样 也不为过”,(1.) 表示允许或请求允许。 You may keep this one, but you mustnt keep that one. May I speak to Janet? * might 表示现在时态的请求允许或允许，但语气比may更委婉,客气。 You might study in our room. Might I give you a piece of advice?,may,May,2. may (might),(2.)表示猜测(只能用在肯定,否定句中)如： She may be on her way home at this moment. She may not like this place. *might可以表示过去时态的“可能”。如： She told me she might come tonight. I am afraid she might think it was just a joke. *表示现在时态的“可能”，might语气比may 弱。如： He might know her address. Be careful , you might fall down.,may (might),(3.)表示祝福,如： May you succeed! May you live long!,may,may / might well动词原形或 may/ might as well动词原形,“还不如，不妨，还是的好”,We may / might as well have something to eat .,3. must,(1.)表示“必须”，如： We must think , and well find a way out. 否定式mustnt , 表示“禁止”，“不许”。 如： You mustnt stay here. Its dangerous. *回答用must提问的句子，要用neednt作为否定回答，意为“不必”。 Must I stay in bed all day? No, you neednt / dont have to. Yes, you must.,3. must,(2.)表示猜测，只能用在肯定句中，如： He must be at home now.,must,* must有一种含义：“偏要”“硬要”。 表示说话人对句子主语所发出的动作或行为是不希望的、不满的甚至是生气的。 Why must you be so stubborn ? Why must you be so late ？,have to 也可以表示 “必须”，但： have to强调客观需要，“不得不”; must更强调说话人的主观看法, “必须”. (2) have to 有较多的时态。如： You will have to go back to school to receive continuing education. You dont have to do it. 比较：You mustnt do it.,(1.)用于一，三人称,表示说话人征求对方意见 Shall Li Ping clean the classroom? Shall we have a break?,4. shall,(2.)用于二，三人称,表示说话人给对方的命令，警告，允诺，威胁，决心等语气,*You shall get a prize from me. *Each citizen shall carry his identification card when travelling. *You shall arrive there before sunset . *If you dont behave yourself,you shall be punished. *Nothing shall prevent from us working hard.,5. should,(1) You should stay here. (2) They should be there by now, I think. (3) You are mistaken, I should say. (4) Ask Tom to ring me up if you should see him. (5) Why should you be so late?,表劝告和建议，应该,表推测，按道理应当，估计,表说话人的谦虚，客气，委婉的语气，用于第一人称,用于条件句中，表 “万一”,表语气，译为 “竟然”,ought to (oughtnt to ),(1)表示 “应该” You ought to take care of him. (2)表示推测 He ought to be home by now.,(1) If you will listen to me, Ill give you some advice. (2) Will/ would you please pass me the book? (3) Fish will die without water. If the pure water is heated to 100 , it will boil. (4) The machine wont work.,6. will / would,表意志和意愿,表请求，建议,表习惯性动作, “总是，惯于”,表功能， 意为 “能，行”,7. used to (usednt to / didnt use to),表示“过去常常”,* used to 即可以强调过去的习惯性动作(由动态动词表示)，也可以强调过去的事实或状态(由静态东此表示)，且与现在形成对比;,* would 只强调过去特定情况下的习惯性动作(由动态动词表示)，单纯的过去和现在无关.,I used to like opera，but now Im not interested in it.,She would sit there for hours sometimes ,doing nothing at all .,8. need,作为情态动词时主要用在否定句和疑问句中: He neednt do it now. Need we begin right now?,He needs to do it now. Do we need to begin right now? You dont need to hand it in.,9. dare (darent),表示 “敢; 敢于”, 主要用于疑问句, 否定句和条件从句中, 一般不用于肯定句,Dare you go alone there? The boy darent say so before the teacher. How dare he do such a thing?,情态动词短语的使用:,would like to do would rather do would prefer to do. had better do.,最好做,想做,了解情态动词的完成式用法 (情态动词+have done) 表示对过去情况的猜测或虚拟,表示对过去发生事情的推测用： must/may/might/cant /couldnt + have done,She passed the exam. She must have worked very hard before the exam.,They cant have finished the work so soon yesterday.,She may/might have left before I came here.,用于虚拟语气的情态动词:,should/ ought to have done shouldnt / oughtnt to have done might / could have done neednt have done,本应该做（但事实没做） 本来不应