高中情态动词用法

1、情态动词Modal Verb情态动词主要用以说明说话者对某一行为的态度和观点，包括能力、可能、命令、要求、许诺、威胁等。情态动词没有人称和数的变化，其后面要跟动词原形。英语中的情态动词主要有：can, could, may, might, must, ought to, shall, should, will, would, need, dare等。情态动词概说Can的用法Can表示能力、可能性、允许等，用于指现在或将来。1. 表能力。如： I can speak English. He can lift the huge stone. Can you play the piano?2. 表可

2、能性。如： Hes an hour late, he can have been delayed by rain. What can she mean?3. 表示允许。如： Can I come in? You can borrow my dictionary.4. 表示惊异、怀疑等。如：How can he be so rude? 他怎么能如此粗鲁？Tips：1. Can 与 be able toCan 表示习惯能力，be able to表示经过努力而做成了某事。e.g.I can sing. I was able to overcome that difficulty.2.can neve

3、r/canttoo表示“无论怎样也不过分”，“越越好”e.g.You cant be too careful while crossing the road. 过马路时越小心越好。 You can never do the work too well.这项工作你做的越出色越好。3.cant help(doing sth)=cant help but do sth不禁/忍不住做某事e.g.I cant help wondering what happened to him.我忍不住想他出了什么事 I cant help but often think of my parents.我禁不住经常想到

4、我的父母。Could的用法Could本身表示能力或可能性；多用于指过去，也可用于指现在，指现在时通常表示虚拟或作为can的委婉形式。表示过去的能力。如： He could speak his native dialect before, but he has forgotten almost all about it now. They said they could swim.2. 表示可能性，既可以表示过去的可能性，也可以表示现在的可能性（比can弱）如： He said he couldnt agree more. 他说他再同意不过了。 Could it be Henry? 可能是亨利吗

5、？3. 表示许可。如 Could I help you? （比Can I help you？更婉转） He asked if he could smoke in the hall. 他问他可不可以在大厅里吸烟。Could的用法4. 表示惊异、怀疑等，在表示这种意义时，could和can可以互换，用could时语气较 婉转。如： He couldnt be over sixty. 他不可能有六十多岁。5. 用于虚拟句中。如： If the door were unlocked, the house could be robbed. 如果不锁门，房子就有可能被盗。 If you had worke

6、d harder, you could have succeeded. 如果你工作再努力一点的话，你原本是可以成功的。 May的用法1. 表示可能性，比can弱， 常用于肯定和否定句中，指现在或将来的可能性。 It may be true. 那可能是真的。 He may not be at home.他可能不在家。2. 表许可，多用于肯定句和疑问句中，否定句中不常用。 You may stay here. 你可以呆在这儿。 May I ask you a question? (比Can I ask you a question更礼貌)3. 表愿望。如： May you live long! 祝

7、您长寿！ May you be happy all your life. 祝您一生幸福。4. 与well, as well或 just as well 连用，表示“完全有理由”或“还是的好”，如： You may well say so. 你完全可以这样说。 You may as well stay where you are. 你最好就呆在原地。(may as well，固定 短语，“不妨”) May的用法补充句型：It may well be that = probably 表示“可能”It may well be that the train is delayed. 火车很可能延迟了。M

8、ight的用法表可能。（可能性比may更小） He might never come.2. 表过去的许可。 Might we ask you a favor? 我们可以请你帮个忙吗？3. Might have done 表示推测，一般不用于疑问句，表示（过去）可能做了某事。 Mike might have got lost. 迈克可能迷路了。 Might have done 表虚拟语气，指本可以做（实际未做） You might have considered her feelings. 你本应考虑一下她的感受。4. 与well，as well或just as well连用，表示“有道理”“不

9、如”，比may更婉转。 You might as well speak your mind. 你不妨把心里话讲出来。 Must的用法表“必须”、“一定”：可用于肯定、否定和疑问句： You must finish your homework. 且用于否定句时，即mustnt，表示“禁止”、“不能”： You mustnt leave here. Cars mustnt be parked in front of the entrance. 车禁止停在入口处。(b) 对于must开头的一般疑问句，肯定回答用must： - Must I come over tonight? 我今晚必须要来吗？ -

10、 Yes, you must. 是的，你必须来。 否定回答要用neednt或dont have to： - No, you neednt.或 No, you dont have to. Must的用法2. 表推测，意为“准是，一定是”must表示推测时只用于肯定句；否定句或疑问句要把must换为can： It must be true. It cant be true.(b) Must表示对现在状况的推测时，后接动词原形： He must earn a lot of money. 他一定赚了一大笔钱。 Must表示对正在进行状况的推测时，后接动词ing： He must be writing

11、a letter to his girlfriend. Must表示对过去发生的事的推测，后接现在完成时： He must have arrived here.(a) Must的用法3. 表示“偏偏”，通常指令人不愉快的事： Must you make so much noise? Why must you always interrupt me ?在表示“必须”这个意思时，must和have to时很接近的，只是have to比较强调客观需要，must着重说明主观看法：I must wash the clothes. 我该洗衣服。（主观想法）I have to wash the clothe

12、s. 我必须洗衣服。（客观需要）Must与have toShall的用法1. 表示建议。用在问句中征求对方的意见和指示，这是可以用于第一人称和第三人称。 Shall I turn on the light? 我把灯打开好吗？ What shall we eat? 我们该吃什么？（征求对方建议） （比较：What will we eat? 单纯指未来吃什么） Shall he come to see you? 你要不要他来看你？2. 表示命令。用于陈述句，一般用于第二、三人称，表示许诺、命令、警告或强制，或表示说话人的决心。 You shant (= shall not) have any. 你

13、一点也别想得到。 You shall be sorry for it one day. 总有一天你会后悔的。 He shall be punished.3. 用于宾语、主语等从句中，表示“应当” She desires that the meeting shall be over soon. 她希望会议能很快结束。 Should的用法1. 表示“应该” You should be more careful next time.2. 虚拟语气 在说明现在或将来时间范畴的情况时，用should属于虚拟用法，与第一人称连用，表示愿望、惊讶或可能性。 I wish that all the thing

14、s should be done at once. They suggested that you should be made a member of the committee. 他们建议你担任这个委员会的饿委员。3. 表示“竟然、居然” I cant believe such a gentleman should be so rude to the old. Ought to的用法(否定为ought not to)表义务。出于责任、义务、道义等方面的要求而该做的事。如： Such things ought not to be allowed. 这种行为是不被允许的。2. 表可能性。 Jo

15、hn ought to know how to use the machine. 约翰可能知道怎么用这个机器。Ought to与Should的区别在多数情况下，ought to与should意义相同。不过，在表示义务时，ought to和should意思相近，但有一些差别。要表示因责任、义务等该做的事时，常用ought to；在表示某件事宜于做、应该做时，多用should。You are his father. You ought to take care of him.We should not use too many big words in our composition.Will的用

16、法1.表意愿或决心She says she will try her best to help me.2.表示请求、邀请，常用于疑问句：Will you mail this letter, please? 请把这封信替我寄一下好吗？Wont you go to the party? 去参加晚会好吗？Pass the book, will you? （祈使句构成反意疑问句时，通常在句尾加will you）3.表习惯或特征，“总是”She will ask some strange questions .她总是问一些奇怪的问题。 Would的用法Would作情态动词时，表示主观意志、可能性、有倾向

17、或有条件性的习惯。用于所有人称。 He wouldnt go ,so I went instead of him.2. Would作情态动词还可表示请求或征求意见。 Would you like a cup of tea?3. 用于虚拟语气 If I were you, I wouldnt go. 我要是你，我就不去。4. 表示重复发生的动作 Sometimes he would come to see us. 他有时来看看我们。5. 表示一种倾向 He said the door wouldnt open. 他说门打不开。 Need的用法Need既可做情态动词，又可做实义动词。用作情态动词时

18、，只有一种形式，后跟不带to的不定式，只用于否定句和疑问句。表示必要性。 You neednt hurry. 你不必急。(neednt 意为“不必”)2. 用于虚拟句中。 We neednt have hurried. 我们当时不必那么匆忙。Dare的用法Dare既可做情态动词也可做实义动词。作情态动词时，它只有一种形式”dare”，后跟不带to的不定式，表示“敢于”，指现在或过去，多用于否定句、疑问句和条件句或表示判断的句子。Dare you jump down from the tree? 你敢从树上跳下来吗？How dare you be so rude? 你怎么敢如此无礼？Dare还可

19、作实义动词，作实义动词时，他有动词的全部形式，后面要跟带to的不定式。She didnt dare to go by herself. 她不敢一个人独自去。1.Although you _find bargins in London,its not generally a cheap place to shop.A.should B.need C.must D.can2.-Ive prepared all kinds of food for the picnic. - Do you mean we_bring anything with us?A.cant B.mustnt C.shant D

20、.neednt3.It was sad to me that they ,so poor thenselves,_bring me food.A.might B.would C.should D.could4.Life is unpredicatable;even the poorest_become the richest.A.shall B.must C.need D.might5.When I was a child,I _watch TV whenever I wanted to.A.should B.could C.must D.needDDCDBTips情态动词have done，

21、一般有两个用法（1）用于虚拟语气表与事实相反的事；（2）只表示推测（1）Should have done： 一般只用在虚拟语气中，表“本应该”； 否定为should not have done，表“本不应该”e.g. The work should have been finished yesterday. 这项工作本应该在昨天就完成。（2）could have done：用于虚拟语气，“本能够做”e.g. He could have pass the exam, but he is too careless.Tips（3）Might have done: 用于表推测，意为“可能”：Mike

22、might have got lost. 用在虚拟语气中，“本可以”：The proposal might have been refused. 这项提议本可以被否决。（4）must have done一般只表示推测，意为“（过去）肯定做了某事” e.g. Since the road is wet, it must have rained yesterday. 注意：其否定为 cantcouldnt have done “不可能” could have done本能够做而实际未做 might have done本可能做而实际未做 should have done本应该做而实际未做 needn

23、t have done本不必做而实际未做 must have done对过去表示肯定的推测 may have done对过去情况的推测，可能.小试牛刀You _ yesterday if you were really serious about the job. A. ought to come B. ought to be coming C. ought to have come D. ought have come2. My wallet is nowhere to be found. I _ when I was on the bus. A. must drop it B. should have dropped it C. must have dropped it D. had dropped itJohn _ be in the classroom because I saw him in the library. A. mustnt B. isnt able to C. cant D. may not_ my g