modalverbs.ppt

1、Modal Verbs,介绍 用法&比较 表推测 表虚拟,介绍,1、情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语。 2、情态动词无人称和数的变化, 情态动词后面跟的动词需用原形(M.V.+ do / be doing/have done),否定式构成是在情态动词后面加 “not”。 个别情态动词（can ,will,may,have to,dare,need）有现在式和过去式两种形式。 3、过去式（might,could,would）用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在或将来。,1. We can

2、 be there on time tomorrow. 2.May I have your name? 3.Shall we begin now? 4.You must obey the school rules. 5. How dare you treat us like that！ 6.He could be here soon. 7.Im sorry I cant help you. 8.He must have been away. 9.You should have told him the news yesterday. 10.Must you play the piano at

3、this time? It is so late now 11. When I was a child I would sit in front of the house ,waiting for my parents. 12. It is strange that he should have done that thing.,用法（本意）&比较,must 必须（命令），必定（推测） mustnt do 禁止做某事 e.g.1 I must finish my work today. 2.You mustnt work all the time. 3.Must I return the bo

4、ok tomorrow? 4.After such a long walk, you must be tired. 5.He must be the man I am looking for. 6. -Must we read this book tonight? - Yes, you must (No, you neednt.),must (主观认为) Vs. have to（客观所迫）,It is raining outside, so I _ take an umbrella. 2. _ I finish it now?,2. Can 能够（能力,许可），可能（通常用于否定推测） can

5、t 1._ 2._ could 能够(过去/现在：语气委婉)，有可能（语气较弱） e.g.1Can you pass me the books? 2.Could you help me, please? 3. It could be Marys as she likes green. 4. It cant be Mary as she is in America now.,can Vs. be able to 能与其他情态动词连用的只能是be able to 2. be able to 更强调做成了，而can 指有能力但不一定成功 I am sure I will_ finish the jo

6、b soon. Finally he _ swim to the shore and was saved.,3. May 可以（许可，同意），可能（推测） may not 1._ 2._ might 可以（过去/现在：语气委婉）有可能（推测，语气较弱） 1.- May I come in? - Yes, you may(can). No you cant. 2. Might I borrow some money now? 3. He might be alive. 4. He may come here by train, but he has his own car.,4. Will 将要

7、，将会（将来时：决心，愿望）；愿意(will not 拟人用法) would 1._ 2._ 3._ e.g. 1. Ill do my best to catch up with them. 2. He said he would help me . 3. Would you please help me? 4. If he will help us, he will do it. 5. The door wont open. 6. When I was there, I would visit the cafe after work every day.,5. Should 应该（建议，命

8、令，要求）；按常理推测； 竟然（惊讶） 1.You should hand in the exercise book. 2.This should be no problem. 3.Why should I meet him？ 4. It is strange that he should have used up all the money intended for dog food. 5. The suggestion that we should start early is worth considering.,should (责任) Vs. ought to（义务） We _ fig

9、ht againt the bad deeds. The police _ fight against the bad deeds,6. Shall 1. 一、三人称疑问句表征求对方意见 2.二、三人称陈述句表威胁、命令、允诺、 规定 e.g. 1. When shall we go? 2. Shall he come in? 3. Lets go, shall we? 4. You shall get no money from me, if you go on doing that. 5. Anyone who steal the gold shall be put in prison.

10、6. You shall get a gift if you do it well.,7. need 需要与 dare 敢 实动(s, ed)：need to do dont need to do dare to do dont dare to do 情动（ed）: need(not) do dare (not) do need doing= need to be done e.g.1. I need a rest. 2.You need to clean the room every day _ 3. He doesnt need to clean the room every day._

11、4. He didnt dare to go out at night. _.,情态动词表推测,不可能,必定,cant,must,might (not),may (not),could (not),1. 基本原则 can 用于否定句或疑问句 must 用于肯定句（陈述句） may might could 肯定句或否定句 e.g.- Can it be Mary? - Yes,it must be her. - No, it cant be her - Im not sure. It might/ may/ could be her. 注：Training by yourself can be

12、highly dangerous 时态问题 M.v. + do / be doing/ have done be +adj. be + n.,3. 关于反意问句 1. He cant be there now, _? 2. There must have been a village in the past ,_? 3. The children must have known the truth till now, _? 4. Mr. Wang cant have been here last night,_? 5. The man must be a thief,_?,情态动词表虚拟(与事实相反),表虚拟语气的情态动词有：would , could , should, might （ought to , need ） 时态问题,e.g. 1. If he had time next week, he would take a few days off. 2.You neednt have told him about it.,M. v. + have done,m