情态动词（复习篇）.ppt

1、情态动词(modal verb),1）情态动词除ought和have外，后面只能接不带to的不定式。,2）情态动词没有人称，数的变化，即情态动词第三人称单数不加-s/ed/ing。,3）情态动词没有非谓语形式，即没有不定式，分词，动名词等形式。,情态动词的语法特征,情态动词主要有：,1）can/ could：否定或疑问的推测：不可能/可能吗 2)may/might：可能性的推测：可能 3)must ：肯定性的推测：想必 4)should/ought to ：应该 5)need(需要) /dare(敢)主要用在否定和疑问句中 6）shall/will/would在一定场合下也可以用作情态动词,1

2、.can表示能力(体力或脑力) I can speak English while he cant . What he said yesterday afternoon could not be understood by anyone present. 2.表示允许 Can I sit here?/You can sit here. 3.表怀疑（在否定句和疑问句中，表疑问、惊异、不想信等态度） Mr. Bush is on time for everything. How can it be that he was late for the opening ceremony?,can/cou

3、ld (can表现在的能力，could表过去的能力),4.表可能性（常出现在否定句中，如用在肯定句中则表示理 论上的一种可能性或有时候可能会 Even an experienced teacher can make mistakes. Shanghai can be very cold in March. （1）can表示推测“可能性”时，往往用于否定句或疑问 句。cant“一定不”，can在疑问句中意思是“会、可能” He cant be at home. = It is impossible that he is at home. 他一定不在家。（This cant be true.） W

4、hat can it mean? （2）can /cant+ have done，表示对过去发生的动作进行推测。He cant have gone to Shanghai for I saw him a minute ago. 他不可能去了上海，我刚才还看见他。Its so late. Where can she have gone? 天晚了，她可能去哪儿了呢？,-Look, someone is coming. Guess_ .-Jack. Hes always on time.A. who can it be B. who he mayC. who he can be D. who it

5、can be,can, could & be able to 的区别,Well be able to finish the work soon.,1.can只用于现在式和过去式(could)。beableto可以用于各种时态。,2.can的主语是人或物,be able to的主语是人,She can/be able to sing the song in English.,3.表示特定的某一过去能力或表示成功地做了某事时，只能用was/wereableto，不能用could。,Although the soldier was badly wounded, he was able to tell

6、 what had happened.,I havent been able to see the film.,The computer can make you feel comfortable.,She ran fast but she couldnt/ wasnt able to catch the bus.,may/might 1）表示询问征求别人意见或允许 -May I come in?-Yes,please. May I ask you a question? You may stay here as long as you like. 2)表示判断和猜测,”或许，可能”表示没有把

7、握的推测（might不表示过去时态，只是语气上比may更委婉，表示的可能性更小） He may come, but I am not sure. These students may / might have seen the film before. Dont throw the empty bottle out of the window.You might hurt someone.,注：may, might表推测时，可以用于否定句，意思是“可能不、也许不”，但不用于疑问句。He may / might not be at home. 他也许不在家。,3.表示祝愿 May you hav

8、e a happy holiday！ May God bless you! 注意： 1）may/might as well，意为“不妨，最好”。If that is the case, we may as well try.may well +动词原型，表“完全能，很可能” He may well be proud of his son. 2）might+have+p.p表示虚拟，表“劝告、责备之意 You might have told me earlier.,must 1.表示“必须” You must finish your homework at once. we must rely

9、on ourselves. You will have to wash your own clothes when you join the army must表示主观, have to表示客观需求. 用于否定句中,表禁止或不可以 You mustnt play with fire. You mustnt play football on the road.,2.表“偏偏”，指发生了令人不愉快的事 The car must break down just when I was about to start. John, look at the time. Must you play the p

10、iano at such a late hour,3.must表推测只能用于肯定句 She must be hungry. He looked worried. He must have lost his way. 在反意疑问句中，当附属部分含有表示推测意义的 must时，疑问部分的助动词应与must后面的动词在 非推测情况下的用法保持一致。 He must be a worker, isnt he? （现在）他准时个工人，是吗？ You must have learned English , havent you? （完成时）你一定学了好多年英语,是吗？ It must have raine

11、d last night, didnt it? （过去）昨晚一定下雨了，是不是？,will 和 would,Do what you will. If you will help me with my English, I will be very happy.,1.will表示意愿、意志，可用于各种人称,Will you tell him the news as soon as he comes back? Would you please speak again more slowly？,2.在疑问句中,will用于第二人称,表示请求或征求意见,would则语气更委婉,3.will 表经常性

12、，习惯性，倾向性,规律性，能力等意为“经常，习惯，总是” Oil will float on water. The door wont open/shut.(表倾向性) -Would you change this basket for another ? It _ hold water. - OK. Im really sorry. A. wont B. cant C. didnt D. doesnt would 1.表意志 2.表过去习惯 3.表请求 She said she would take care of the child. He would sit near the fire

13、for hours on winter evenings. would表意愿的短语 would rather 宁愿 would like 喜欢，想要（=would love）,shall 1.在疑问句中，用于第一、第三人称，用来征询对方意见或请求指示。 Mr. Smith wants to see you, manager. Shall he wait outside or in the office? Shall we begin at once? 2. 用在第二、第三人称之后表示说话人的“许诺、警告、命令、威胁”等意愿。 You shall have the story-book as s

14、oon as I finish reading it. You shall fail if you dont work harder. He shall be punished.,3.用于所有人称，表规章，法令，预言等，译“必须” It has been announced that candidates(候选人) _ remain in their seats until all the papers have been collected. A. can B. will C. may D. shall,should /ought to,1.表义务，责任或劝告，建议，命令 意为“应该” Yo

15、u should be more patient. You should do it better next time. We ought to help each other. 2.表示可能性、推测 “理应，按说该”,有一定 的理论依据 My sister should be home by now. 我妹妹现在应该到家了,3.表示惊异、赞叹、不满等情绪：It is simply a miracle that rice should grow in such a place. 稻子竟能在这样的地方生长，这实在是个奇迹。Its wonderful that you should get ful

16、l marks. 你得了满分真了不起。Why should you be so late today？ 你今天怎么来得这么晚？You cant imagine that a well-behaved gentleman_ be so rude to a lady. A.might B.need C.should D.would,4.（表示语气较强的假设）万一，竟然. If he should fail to come, ask Tom to work in his place. 万一他不来，就叫汤姆代替他工作。,should/ought to have done might have done could have done need not have done,情态动词+have+done” 表“本来” 使用情形分析,情态动词的否定式,cant:不能；不可能 may not:可能不 mustnt:不准；不许；禁止 neednt:不必 darent:不敢 wont:不愿意，就是不 shant:决不 shouldnt:不