情态动词情态动词 can( could) must have to may(might) dare(dared) be able to shall(should) need(needed) used to will(would) ought to had better 情态动词无人称和数的变化，不能单独使用，与动词原形共同构成谓语动词 1. Can (could)(1）表示能力，）表示能力， “能，会能，会” can 表示现在的能力，表示现在的能力，could 表示过去的能力，例：表示过去的能力，例：I can speak Japanese, but I cant write it.Could the girl read before she went to school?(2)表示许可，表示许可， “可以可以” ，此时，此时 could 比比 can 更委婉，不是更委婉，不是 can 的过去式。的过去式。 例：例：Could/Can I borrow your pen?eg: Could I borrow your dictionary?Yes, you _.(3)表示可能性，推测，此时表示可能性，推测，此时 could 不表示时态，只表示可能性比不表示时态，只表示可能性比 can 小。小。A 情况情况: 用于否定句和疑问句中， “不可能” （表示具体事情发生的可能性)eg: It _ be the postman at the door.It is only six oclock.A.mustnt B.cant C.wont D.needntB 情况：情况：用于肯定句中， “有时可能会” （表示理论上的可能性，不涉及是否发生） 例：You can hurt yourself if you play in the street.Accidents can happen at any time.(4) can 与 be able to Eg：The fire spread through the hotel very quickly, but everyone_ get out.A.had to B.would C.could D.was able to2.may（might）(1) 表示许可，表示许可， “可以可以” ，此时，此时 might 比比 may 更委婉，不是更委婉，不是 may 的过去式的过去式eg: Might/ May I come in? Yes, you_/ No, you_.(2) 表示可能性，推测，此时表示可能性，推测，此时 might 不表示过去，只表示可能性比不表示过去，只表示可能性比 may 小。小。Eg: Helen _ go on a trip with us,but he isnt quite sure yet.A.shall B.must C.may D.can 注意：can not 不可能 may not 可能不may well 极有可能Eg: Liza may well not want to go on the tripshe hates traveling.may as well 不妨Eg: You may as well stay for dinner.3.must (1). must “必须必须” （主观）（主观） ， have to “必须，不得不必须，不得不”（客观）例：（客观）例：We must rely on ourselves.I cant see things clearly. I have to wear glasses. (2).表式可能性，推测，只用于肯定句表式可能性，推测，只用于肯定句“一定，肯定一定，肯定”eg.The light is still on, so he must be at home. (3)“偏要，偏偏偏要，偏偏” Eg: Why must you always interrupt me? Eg：May I smoke here?If you must, choose a seat in the smoking area. （4）eg: Must I hand in my report today? Yes, you_/No,you_.4.shall(should) (1) shall 用于第一人称，表示用于第一人称，表示“将会，将要将会，将要” 。Eg：I shall be thirty next year. (2) shall 用于一，三人称疑问句，表示说话人征求对方意见。用于一，三人称疑问句，表示说话人征求对方意见。Eg: Shall we/he.begin now? (3) shall 用于二、三人称陈述句，表示说话人的命令，警告，允诺，威胁。用于二、三人称陈述句，表示说话人的命令，警告，允诺，威胁。Eg：You shall go with me.You shall have the book when I finish it.He shall be punished. (4) shall 用于用于 shall 用于条约，规章，法律等文件中，表示一种义务，多用于第三人称。用于条约，规章，法律等文件中，表示一种义务，多用于第三人称。Eg:“The interest _ be divided into five parts, according to the agreement made by both sides.”declared the judge.A.may B.should C.must D.shall(5) should 表示可能性，推测，这种推测有一定根据，表示可能性，推测，这种推测有一定根据， “按理应该按理应该” 。Eg: They should be at home by now, for they have been away for two hours. (6) should 用于一，三人称疑问句，表示说话人征求对方意见。用于一，三人称疑问句，表示说话人征求对方意见。Eg: Should I open the window. (7) should 表示表示“居然，竟然居然，竟然”Eg: I cant believe such a gentleman should be so rude to the old. (8)should “应该应该”（责任与义务）（责任与义务）ought to 意义相近，语气更强，在疑问句中通常用 should 代替 ought to.Eg：You should be kind to your children.You ought to finish your work before you go home.5.will (would) (1) 表示将来，表示将来， “将要将要” ， would 表示过去将要。表示过去将要。Eg： I will tell you all about this. (2) 用于第二人称疑问句，表示请求建议，此时用于第二人称疑问句，表示请求建议，此时 would 不是过去式，比不是过去式，比 will 更委婉。更委婉。Eg:Will/Would you come this way please? (3) 表示意志，愿望，和决心表示意志，愿望，和决心“愿，要愿，要” ，would 表示过去的愿望和决心。表示过去的愿望和决心。Eg: I will never do that again. (4) would do 与 used to do.would do 过去的动作（不一定停止）used to to 过去的动作和状态。 （现在停止了）Eg: He used to be a quite boy.( )He would be a quite boy.( )Eg: When I was a boy, I_ chocolate.A.would like B.was used to like C.should like D.used to like 拓展： Lets do Shall we?Let us do Will you?6: need “需要，必须需要，必须” （dare） (1) 做情态动词做情态动词 （need+do）Eg I need drink some water.否定：_. (2) 做实意动词（做实意动词（need to do）A：主语是人：主语是人 eg: He needs to drink. 否定否定_.B: 主语是物主语是物 eg: The car needs _._.7: 情态动词情态动词+ have donemust have done 一定做了某事一定做了某事may/might have done 可能做了某事可能做了某事may/might not have done 可能没可能没/或许没做某事或许没做某事 can/could have done 本可以做却没做本可以做却没做cant /couldnt have done 不可能做了某事不可能做了某事Should/ought to have done 本应该做实际却没做本应该做实际却没做Should not / ought not to have done 本不该做却做了本不该做却做了neednt have done 本不必做却做了本不必做却做了8.cant + toobe too =最高级 比较级 Eg: I cant agree with you any more. You cant pay too much attention to your reading skill, as it it so important. You can not be careful.