语法专项复习情态动词ModalVerb.ppt

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1、语法专项复习：语法专项复习：情态动词情态动词 (Modal Verbs)常用的情态动词常用的情态动词can（could）may（might）shall（should）will （would）must（must）dare（dared）need（need）have to ought to be able toused tohad better(1)表示能力表示能力:can/could 只能表示只能表示现在现在或或过去过去的能力。的能力。*be able to 能用于能用于各种时态各种时态。*was/were able to:“设法做成某事设法做成某事”相当于相当于 managed to do st

2、h.succeeded in doing sth.。1.1.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 prai

3、se him too much.You cannot be over careful.cannot cant 与与tooover等词连用，意思是等词连用，意思是“越越越越”,“无论怎样无论怎样也不为过也不为过”(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?mayMay 2.2

4、.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(mi

5、ght)(3.)表示祝福,如：May you succeed!May you live long!maymay/might well动词原形或动词原形或may/might as well动词原形动词原形“还不如，不妨，还是还不如，不妨，还是的好的好”We may/might as well have something to eat.3.3.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，

6、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.3.3.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：有一种含义：“偏要偏要”“硬要硬要”。表示说话人对句子主语说话人对句子主语所发出的动作或行为是不不希望的、不满的甚至是生气的。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

7、”，但：(1)have to强调客观需要，“不得不”;(2)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.)用于一，三人称用于一，三人称,表示说话人征求对方意见表示说话人征求对方意见 Shall Li Ping clean the classroom?Shall we have a break?4.4.shall(2.)用于二，三人称用

8、于二，三人称,表示说话人给对方的命令，警告，表示说话人给对方的命令，警告，允诺，威胁，决心等语气允诺，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.5.5.should(

9、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，应该表劝告和建议，应该表推测，按道理应当，估计表推测，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，表用于条件句中，表“万一万一”表语气，译为表语气，译为“竟然竟然”o

10、ught to(oughtnt to)(1)表示表示“应该应该”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.6.6.

11、will/would表意志和意愿表意志和意愿表请求，建议表请求，建议表习惯性动作表习惯性动作,“总是，惯总是，惯于于”表功能，表功能，意为意为“能，行能，行”7.used to(usednt to/didnt use to)表示表示“过去常常过去常常”*used to 即可以强调过去的习惯性动作(由动态由动态动词表示动词表示)，也可以强调过去的事实或状态(由静由静态东此表示态东此表示)，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

12、.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 daren

13、t say so before the teacher.How dare he do such a thing?情态动词短语的使用情态动词短语的使用:would like to dowould rather dowould prefer to do.had better do.宁愿宁愿最好做最好做想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表示对过去发生事情过去发生事情的推测用：的推测用：must/may/might/cant/couldnt+have doneShe passed the exam.She must have worked

14、very hard before the exam.They cant have finished the work so soon yesterday.She may/might have left before I came here.用于用于虚拟语气虚拟语气的情态动词的情态动词:should/ought to have done shouldnt/oughtnt to have done might/could have doneneednt have done本应该做本应该做（但事实没做）（但事实没做）本来不应该做本来不应该做（但事实却做了）（但事实却做了）本来可以做本来可以做（但事实

15、没这样做）（但事实没这样做）本来不需要做本来不需要做（但事实却做了）（但事实却做了）表示否定的情态动词的用法表示否定的情态动词的用法:部分情态动词的否定式是情态动词中的考点之一部分情态动词的否定式是情态动词中的考点之一 mustnt neednt cant may not shouldnt 不准不准,禁止禁止 没必要没必要(=dont have to)不能不能;不可能不可能不可以不可以;可能不可能不不应该不应该(=ought not to)注意情态动词的推测用法注意情态动词的推测用法推测性情态动词共有三个，其用法见表推测性情态动词共有三个，其用法见表 情态动词情态动词 含义含义 适用句型适用句型 may/might可能，或许可能，或许 肯定句肯定句,否定句否定句must 一定一定肯定句肯定句 can/could 可能，或许可能，或许 否定句，疑问句否定句，疑问句