1、Model Verbs情态动词第一部分情态动词的基本用法情态动词表示可能、必要、允许、愿望、猜测等意义，它们本身虽有一定词义，但不能独立用作谓语、也没有人称和数的区别，其后必有动词原形，共同构成复合谓语。can与could的用法1)表能力can表能力时意味着凭体力或脑力或技术等可以做。I can climb this pole.He is only four,but he can read.Fire cant destroy gold.zxxk因为can不能和其他助动词连用，所以表示将来式时用will be able to You will be able to skate after pra
2、ctising it times.2)表可能性Can the news be true?It cant be true.What can he possibly mean?3)表示允许（和may意思相近）常见于口语。Can(May)I come in?我能进来吗？Can I smoke here?我可以在这里抽烟吗？could表过去的能力、可能和许可,（间接引语）I could swim when I was only six.Father said I could swim in the river.3.cannot/couldnt too+副词/形容词;cannot/couldnt+副词/
3、形容词+enough无论也不过分；越越好You cant be too careful when crossing the street.I cannot thank you enough.我对你感激不尽。Can和 could 的一些固定搭配1.Cant/couldnt help doing 忍不住;He cant help laughing.2.Cant/couldnt but+动词原形只好；不得不 I couldnt but admit that he was right and I Was wrong.我不得不承认他对了，我错了。情态动词may与 might 的用法1)表示请求、可以、允
4、许。You may watch TV now.2)当回答由may 引起的问题时，否定答语要用must not,表示“不许可、不应该、不行”。May I come in?(=can)学科网Yes,you may.No,you mustnt.3)表建议（可和as well 连用）You may as well stay where you are.Might 1)表过去的“可能”和“允许”多用于间接引语。She said that he might take her dictionary.除在间接引语中外，might一般不表示过去的“可能”与“许可”。表过去的“可能”可用could，表过去的“许可
5、”可用were(was)allowed to。2)表现在的“可能”，其可能性要比may小。Electric irons could be dangerous;they might give you a severe shock.may 和might 的某些固定搭配1.may well+动词原形理应；有足够的理由We may well say she is a good teacher.我们大可说她是一位优秀的老师。2.may/might as well+动词原形不妨；还不如 You never listen-I might as well talk to a brick wall.你从来不听我
6、的话，我还不如对着一堵墙说话。3.maybut 或许会但是 She may be beautiful,but she is cool.她也许算的上美丽，但太冷漠了。情态动词 must与have to 的用法1、must 的主要用法。1)表示必须、必要We must do everything step by step.2)must 的否定式有两个：当回答由must引起的问题时，否定答复要用neednt或dont have to表“不必、无须、用不着、不一定”的意义。当表示“不应该、不许可、禁止”时，就用must not。Must I go tomorrow?Yes,please.No,you
7、neednt.(=dont have to)You must not smoke here.你不准在这儿吸烟.have to的含义与must是很接近的,只是have to 比较强调客观需要，must着重说明主观看法。I must clean the room.（主观想法）Its getting late.I have to leave now.（客观需要）另外，have to 能用于更多时态：We had to be there at ten.We will have to reconsider the whole thing.have to 的否定式：dont have to do“不必做”
8、。You dont have to go right now.情态动词ought to 的用法。Ought to 后接动词原形，表义务，但不及must 那样具有信心，如：You dont look well.You ought to go to the doctor.Ought to 用于否定句，可缩略为oughtnt to。You oughtnt to smoke so much.也可以用于疑问句，如：Ought you to smoke so much?Ought to 在间接引语中表过去时形式不变,如：He said you ought to tell the police.情态动词sh
9、all与should 的用法1、shall的用法1)用于第一人称征求对方的意见，如：What shall I wear on the journey?Shall we dance?2)shall 用于第二、三人称时表允诺（现已少见），如：She shall get her share.You shall have it back tomorrow.shall表示说话人的意愿，有“命令、允诺、警告、决心”等意思，用于第二、三人称陈述句中。You shall do as I say.(命令)Nothing shall stop us from carrying out the plan.(决心)H
10、e shall have the book when I finish reading.(允诺)You shall fall behind in your exam if you keep playing.(警告)情态动词should主要用法有：1)用于第一人称疑问句中询问对方的意愿，但语气较委婉温和，如：What should we do now?我们现在该怎么办？2)表示应该、必须，常与must 换用。例如：We should(must)master a foreign language at least.3)在“It is natural,strange,necessary,surpri
11、sed,impossible,important+that”句型中，在“It is suggested/ordered/demanded that.”句型中，主语从句中的谓语动词要用should+动词原形”表示“理所当然”、“奇怪”、“必要”、“惊异”等的意思。在lest（以免）、for fear(that)(以防)、in case（以备万一）等之后也要用“should+动词原形”如：It is necessary that he(should)be sent there at once.It is strange that he should say so.Let us go at once
12、 lest we should be late for the train.情态动词will和would的用法1）表示意志，决心或愿望。例如：Surely we will support all the people in the world in their struggle for peace.He would not let me try it.2）will表示经常性、习惯性、倾向性，would表示过去的习惯行为。(必须与行为动词连用，would=used to)He will sit there hour after hour looking at the traffic go by.
13、He would come to see me when he was in Beijing.3）用于第二人称作主语的疑问句中，表示对对方的请求，would的语气比will委碗Would/will you kindly tell me the way to the station?情态动词need和dare的用法这两个词只能算“半情态动词”，它们作情态动词用时，一般用在否定句和疑问句中，如果用在肯定句中，多数是实义动词，一般现在时单数第三人称就要加s，并有时态变化，后接不定式时须带to,试比较：Need I explain once more?（情态）The question needs to
14、 be discussed.（实义）She dare not tell the truth to you.（情态）We should dare to think,to speak and to act.（实义）She doesnt dare to go out at night by herself.（实义）She dare not go out at night by herself.（情态）第二部分 情态动词的推测用法从推测角度分：可能(1-50%)might;may;could;can很可能(6090%)should;ought to;would肯定(100%)must不可能(0%)ca
15、ntmust表示推测时，它的肯定程度比 may,might，could大得多，一般只用于肯定句。may,might表示推测，一般只用于肯定句。可译为“可能，也许”。(一般情况下，might表示的可能性很小)can和could表示推测，可用于肯定句(can罕见)、否定句和疑问句，但更常见于疑问句或否定句。在此种用法中can和could没有时态的区别，只是表示可能性的大小，can表示推测的可能性比could大。should表示对过去、现在或将来情况的某种推测，可译为“可能、照说应该”。一般用于肯定句，可指人的直觉或个人看法。It should be fine tomorrow.ought to表示
16、推测，暗含很大的可能，可译为“应该是，会是”。一般用于肯定句，可指人的直觉或个人看法。Prices ought to come down soon.从形式角度分一般式Model V.+be/do进行式Model V.+be doing完成式Model V.+have doneHe should be back now.He must be watching the live football match.They may have arrived there.他们可能在等我们，赶快点！他们可能在干什么呢？他不可能在看电视，一定在看书。你想必把此事忘了。咱们去问问他，他也许看过这部电影。大桥不可
17、能这么快就竣工了。They may be waiting for us.Lets hurry!What can they be doing?(might/may)He cant be watching TV.He must be reading.You must have forgotten it.He might have seen the film.Lets ask him.The bridge cant have been finished so soon.当情态动词表示推测时，其所在的句子的反意疑问句的简短问句应与情态动词后的主要动词的形式相呼应。Model V +be 是对现在所作推
18、测，反意问句应作为一般现在时或现在进行时处理。He may be in the library,isnt he?(Im afraid)He is in the library,isnt he?They cant be playing on the playground,are they?(Im sure)They arent playing,are they?Model V.+have done 是对过去或人生经历所作推测，反意问句应作为一般过去时或现在完成时处理。You must have seen the film yesterday,didnt you?组卷网 He cant have
19、missed the train then,didhe?She must have been to the Great Wall,hasnt she?They may have lived here for a long time,havent they?第三部分情态动词的虚拟用法couldhave done本来可以做惋惜mighthave done本来也许可以惋惜neednthave done原本不必做惋惜shouldhave done本应该做责备shouldnthave done本不应该做责备ought tohave done本应该做责备 I could have passed my examination easily but I made too many stupid mistakes.If we had taken the other road,we might have arrived earlier.You neednt have watered the flowers,for its going to rain.I should have thought of that.They should not have left so soon.You ought not to have been so careless.
