情态动词复习.doc

情态动词用法归类
（一）表达“情感、态度、语气” 等方面的情态动词
1. must表达“情感、态度、语气”主要有以下用法：
(1) 表示主观的义务和必要，主要用于肯定句和疑问句，意思为“必须……，
由must引起的疑问句，肯定回答要用must或have to，
否定回答要用needn’t或don’t have to,意思是“不必”。
另外，must与have to区别： must表示一种主观的需要，而have to表示一种客观的需要，意思是“不得不”，其否定形式是don’ have to。
-What sort of house do you want to have? Something big?
--Well, it ______ be big--that's not important.
A. mustn't B. needn't C. can't D. won't
(2) must的否定形式mustn’t表示禁止，意思是“不能，不许”。例如：
When I was young, I was told that I ______ play with matches
A. wouldn't B. needn't C. mustn't D. daren't
(3) must用于条件句或疑问句中，可以用来表示责备、抱怨的感情色彩，意思为“偏要，硬要、干嘛”。例如：
①—May I smoke here ?
—If you ____, choose a seat in the smoking section.
A. should B. could C. may D. must
②John, look at the time. ___________ you play the piano at such a late hour?
A．Must B．Can C．May D．Need
2. should
(1) should应该，表示“责任和义务”。例如：
According to the air traffic rules, you ___ switch off your mobile phone before boarding.
A. may B. can C. would D. should
(2) should还可以用来表示说话人对某事不能理解、赶到意外、惊异等意思，译为“竟然，竟会”。例如：
You can’t imagine that a well-behaved gentleman _____ be so rude to a lady.
A. might B. need C. should D. would
3. shall
(1) shall用于第一和第三人称，常用于疑问句中，用来征求对方意见。例如：
—What’s the name?
—Khulaifi. _________ I spell it for you?
A. Shall B. Would C. Can D. Might
(2) 用于第二和第三人称，表示“命令、威胁、警告、允诺、”等。例如：
—Excuse me. But I want to use your computer to type a report.
—You _____have my computer if you don’t take care of it .
A. shan’t B. might not C. needn’t D. shouldn’t
(3) shall也用于宣布法律、规定的要求。例如：
—What does the sign over there read?
—“No person ________ smoke or carry a lighted cigarette，cigar or pipe in this area.”
A. will B. may C. shall D. must
4. can
(1) can可以用来表示惊异、怀疑、不相信的态度，主要用于否定句、疑问句或感叹句中。例如：
How ______ you say that you really understand the whole story if you have only covered only part of the article?
A. can B. must C. need D. may
(2) can也可以用来表示请求或许可。(could更委婉)例如：
—Mum, I’ve been studying English since 8 o’clock. ______I go out and play with Tom for a while?
—No, I’m afraid not. Besides, it’s raining outside now.
A. Can’t B. Wouldn’t C. May　　　D. Won’t
(3) can可以表达一般的或永久的能力。be able to常用来表达在某件事情中所表现出来的能力，尤指克服困难能够完成某事。例如：
The fire spread through the hotel very quickly but everyone ______ get out.
A. had to B. would C. could D. was able to
5. would
(1)will与would可表示“意愿；意志 ”。
John promised his doctor he _____ not smoke and he has never smoked ever since.
A. might B. should C. could D. would
(2) would表示过去倾向性或习惯性的动作。used to 也有这一用法，但used to表状态的词一起用。例如：
When he was there, he ___ go to that coffee shop at the corner after work every day.
A. would B. should C. had better D. might

6.may, might的用法
1】 表示允许、请求。Might I …？ 比 May I …？ 语气更委婉和有礼貌。
Might I close the window?
2】表示可能性，表示“或许，大概”。用于肯定句或否定句中，用might 比 may语气更加不肯定。
3】表示祝愿。(不用might)采用部分倒装语序：may＋主语＋动词原形＋……
May you succeed!
May the friendship between us last forever!
肯定回答：may/can 否定回答 can’t / mustn’t

7.ought to表示责任和义务“应该”，语气比 should强；还可表推测。
You ought to finish your work before you go home.
You have practiced for a long time. There ought to be no difficulty for you.

8.need的用法
1】need作情态动词表示“需要”，“必要”。通常用于否定句、疑问句、条件句中，且只有现在时，其他时态用“have to”的相应形式代替。
You needn't water the tomato plants now.
— Need he come now?
— Yes, he must. / No, he needn‘t. / he doesn’t have to.
2】need还可以用作行为动词，
The house needs repairing. ＝The house needs to be repaired.

（二）表示推测的情态动词
对现在或将来情况推测，用情态动词+do / be / be doing…；
对过去的推测，用情态动词+have done / been…；
Must +be doing 表示对现在的动作进行肯定推测
Must +have done 表示对过去发生的事情作出的肯定判断
can/could have done 对过去发生行为的可能性进行推测；本可以，本应该
might/may have done,表示对过去发生的动作进行可能性推测，
I ＿ have passed my examination easily, but I made too many stupid mistakes.
A. must B. will C. shall D. could

表示肯定推测的情态动词按可能性大小依次为 must, should / ought to, may, might, could；
否定推测，常用can’t / couldn’t，译为“根本不可能”、“想必不会”，表示推测的语气非常肯定
may not, might not或could not译为“可能不”、表示推测的语气不很肯定。

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