高中英語情態(tài)動詞講義

1、情態(tài)動詞情態(tài)動詞也稱為情態(tài)助動詞，除了幫助句子中的謂語動詞構(gòu)成否定/疑問時態(tài)/ 語態(tài)等，自生還有其基本詞義.表示說話人的需要、猜測、意愿或懷疑等.一、情態(tài)動詞的特征1 .情態(tài)動詞沒有人稱和數(shù)的變化，即情態(tài)動詞第三人稱單數(shù)不加-s （have to, have got to, be able tc除外。2 .情態(tài)動詞不能表小正在發(fā)生或已經(jīng)發(fā)生的事情，只表小期待或估計某事的發(fā) 生。3 .情態(tài)動詞是互相排斥的，一般不允許兩個意義相近的情態(tài)動詞連用?！菊`】 Can I be able to borrow two books at a time?【正】Can I borrow two books at

2、a time?我能一次借兩本書嗎？【正】W川I be able to borrow two books at a time ?我能一次借兩本書嗎?二、情態(tài)動詞白意義和用法（請求許可/推測可能/能力才能/要求建議/意志決心（一請求許可Can/could/may/mightl.can/couldcan:表示說話人和一般的許可，用于肯定句和否定句，也可以用于疑問句中， cannot表示禁止”但在正式場合下不能使用（文書/公告。could主要用于疑問句，比 用can更加遲疑不決，當沒有把握得到允許時，這樣更婉轉(zhuǎn)。答語要用can.e.g Can I go with you?-Could I use yo

3、ur phone? -Yes, of course you can. You cannot smoke in the office. These days children can do whatever they want.2. may/might同can相比，may和might用于比較正式文體，往往含有尊敬之意。用于肯定，疑 問和否定句。May not用于拒絕給予許可，或禁止做某事，通常在正式的官方公告 中.might表示比較遲疑，婉轉(zhuǎn)。用于非常正式的場合，不很常用，在給予被人許可時常 用can,有時也用may,但不能用might.e.g May I come in please? I w

4、onder if I might speak to your son.-May I turn on the CD player?-No, you may not/ cannot/ No, you mustn't.具有強烈禁止的意思（不可說:No, you might not Any book may not be taken out of the library. Cars may not be parked in front of the hall.總結(jié):表示請求許可是can/could/may/might禮貌程度依次遞增.肯定回答常 用:Yes, you can/may.否定回答常

5、用:Sorry, I am afraid not.或I' rather you didn 或 t No, you may not/cannot.3. must : 一般用于否定句。 must not比may not更為強調(diào)。e.g. You mustn't play football in the street, children.4. shall:一般用于第一，三人稱疑問句中e.g Shall I open the window? Shall he come to see you?肯定回答,一般是 of course;certainly;yes, please 否定回答，一般

6、是 no, thanks5. will/would: 一般用于第二人稱，would更客氣。e.g. Will/Would you spell your name?（二推測可能1. can/could:1表示邏輯上或理論上的普遍的或者偶爾的可能性，而不是某種實際上將要發(fā)生 或正在發(fā)生的可能性，并非說話人的主觀猜測。e.g. Anybody can make mistake.縉遍性 The weather here could be very cold in winter.偶爾的2說話人主觀的猜測 可能”多于be連用。多用于疑問句或否定句中。Can和could沒有事態(tài)的差別，只是could不太肯定

7、。e.gD He can't be at home. Can the news be true?注意:不表示某事實際發(fā)生的可能e.g. It can rain this evening.俁2. may/might表示事實上的可能,某事未來或正在可能要發(fā)生。might表示的可能性比may 小一些。一般用于肯定和否定陳述句：May+ do/be doinge.g It may/might rain tomorrow.明天可能下雨。Let' s speed up. They may/might be waiting for us now.注意:和can not的區(qū)另U: (may n

8、ot:可能不;cannot:不可能e.g He can't be at homeffc 不可能在家。He may not be at home他可能不在家。用法比較：might/may/could/can表示可能性時的從小到大e.g. You might/may/could/can be right.(能性：30%-40%-50%-60%3. must: 一般用于肯定句，否定句或疑問句中用can代替(cannot/Can？1表示說話人的對現(xiàn)在/正在進行/將來的動作或狀態(tài)非?？隙ǖ挠懈鶕?jù)的推測。Must+ do/be doinge.g You must be ill. I can see

9、 it form your face.® Something must be burning. I can smell it. Bell must be leaving tomorrow.2表示根據(jù)邏輯必須發(fā)生的事。e.gAll men must die.人都是要死的。Winter must be followed by spring.冬天到了，春天還會遠嗎？4.will/would1表示說話人對將來和現(xiàn)在的預測。e.g. I think he will/would be all right now.我想他現(xiàn)在一定好了。2有時表示某種傾向和習慣性。Would do可表示過去常常。e.

10、g Oil will float on water.油浮在水面上。Why don t you put the meat in the refrigerator? It will stay fresh for several days.He would get up very early.過去他常常起的很早5. ought to:一般用于肯定。e.gThey ought to be there by now.他們現(xiàn)在一定到那了 .They ought to win- they have trained hard enough他們應該能贏，他們訓練的夠 苦的。6.shall/should:表示說話

11、人的猜測，多指預期的事，表示:估計應該/按道理應該。e.gI shall be rich one day.總有天我會發(fā)財?shù)摹?That should be Janet coming upstairs now£ 在上樓的準是珍妮特。（三能力才能can/could/be able to:表示人或動物的內(nèi)在能力。有某種知識或者技能而能夠做 某事。用于肯定，否定和疑問句。e.g. He can/is able to speak two foreign languages.注意:can與be able to用法上的區(qū)別：1. can只有兩種時態(tài),即can和could;而be able to有將

12、來式，完成式等多種時 態(tài)。但二者均無進行時態(tài)。e.g I ' ll be abl e to drive the car in a week. Tom has been able to drive.2. 表示過去通過努力終于做成了某事要用be able to而不能用can。如：E. g. I was able to swim to the bank after the boat turned over.3. can是情態(tài)動詞，只能用作謂語成分,be able to是普通動詞短語，既可以作謂語， 也可以作非謂語。如：e.g. Being able to speak English flue

13、ntly, he has no difficulty in communicating with the Americans at the party.4. be able to后邊接動詞不定式表示一種實際情況時，其否定形式不是be not able to,而是 cannot。如：e.g. -Were you able to catch the first bus yesterday morning?-No, I couldn ' t.5. 一般說來，be able to后邊的動詞不定式?jīng)]有被動語態(tài)。如：e.g. I ' m sure he is able to correct

14、 his mistakes in grammar.不說:*I ' m sure his mistakes are able to be correbyehim.1 .Be able to前面可以加can以外的情態(tài)動詞。E.g. You might be able to persuade him. I ought to be able to live on my salary.7 . could經(jīng)常和動詞 see, hear, smell, taste, feel, remember, understand連用。不 用 was able toe.g When we went into t

15、he house, we could smell something burning. She spoke in a very low voice, but I could understand what she said.8 .在談?wù)撜f話時發(fā)生的動作，用can不用be able td【誤】Look! I'm able to swim.【正】Look! I can swim.看，我會游泳了 ?。ㄋ囊蠼ㄗh1. must:1用于肯定句，表示說話人的意志和義務(wù)。或要求對方必須作某事。2疑問句用于征求說話人的意見?？隙ɑ卮鹩茫篩es, you must.否定用needn't或 don

16、't have to-Must I finish my homework today?-Yes, you must./ No, you needn ' t./No, you don ' t have to.2. may/might1 may用于法律和條約，相當于shall。用的較少。e.g. A civil juristic act may be in written, oral or other form.民事法律行為可以采取書面形式、口頭形式或者其他形式（中華人民共和國民法通則第56條。2 might用來對人們提出建議，可以用來提出批評，不能與may替換e.g. Y

17、ou might have considered your parents'feelings.3. Shall/shouldShall:1用于第二/第三人稱作主語的陳述句中，表示給對方的許諾，命令，警告,威脅。Eg You shall get an answer from me tomorrow. The children shall get a gift if they are nice. You shall be punished for what you have done.2用于第三人稱作主語的陳述句中，在條約，規(guī)定，法令等文件中表示義務(wù)和規(guī)定 表示應該,必須”e.g. All

18、 payment shall be made in cash.Those belonging to our school shall wear uniform.Should:表示義務(wù)，責任提出建議e.g Today' s children shoullearn to respect their elders. We should take good care of the little kids.® Should I help you with the community affairs?3 Ought toought to強調(diào)在客觀上（法律漳程和道義（或者是自己的意見聽上去

19、像法律和義 務(wù)一樣有力，比should語氣強。e.g. You ought to go and see Mary tomorrow.明天你應該去看瑪麗。We ought to defend our country.我們應當保衛(wèi)我們的國家。（每一個公民應盡 的義務(wù)（五意志決心will/would:可表示意志、愿望和決心，用于各種人稱陳述句。will表示意愿或決 心時，可用于條件狀語從句。e.g.e.g I will do anything for you. I will never tell you the secret. They would not let him in because he

20、 was poorly dressed.If you will give up smoking, your health will improve. 如果你愿意把煙戒掉的 話，你的健康狀況就會好轉(zhuǎn)。三.情態(tài)動詞特殊用法1 .May+主語+動詞原形表示祝愿。e.g May you succeed.祝你成功May that day come soon.希望這一天早日到來。2 .must有時可用來表示偏要/非得”的意思。e.gWhy must it rain today?為什么偏偏在今天下雨？When I was taking a nap, a student must knock at the d

21、oo£當我午睡時 偏偏一 個學生在這個時候來敲門。3 . should表示說話人的驚奇，憤怒，失望的特殊情感，意為:居然/竟然e.gHow should I know where you ' ve left your bag? I am surprised that you should talk with me like that.4 . can用在否定句和疑問句中表示驚訝。e.g How can such a simple meal costs so much? This cannot done by him.四.情態(tài)動詞的習慣用法：1 .Can的習慣用法:2 canno

22、t help doing sth:情不自禁3 can but do:只好4 cannot (help but do sth:不得不5 can not/can never too: 也不過分e.g I cannot help thinking of him when I am lonely. We can but do our best. The girl cannot (help but live on herself. You can never do the work too well.2. may的習慣用法:1 may (might well:很可能2 may (might as wel

23、l:最好，倒不如3. may/mightbut 我承認是事實，但是e.g He may/might well be in the house.他彳艮可能在房子里。 There is nothing to do, so I may/might as well go to bed.It may rain tomorrow, but we ' ve been determined.4.dare的習慣用法：1I dare say:表示猜測，意為:我相信，我認為，很可能2 How dare you/he/she/they你怎么敢?E.g. I dare say you are right.How

24、 dare you come in without knocking the door?五.情態(tài)動詞+ be doing:推測現(xiàn)在正在發(fā)生或存在的狀態(tài)。1 must+ be doing:用于肯定句中，表示 乙定正在”2 Can/can ' t + be do岫F疑問句/肯定句中，表示 可能正在嗎？/不會正在”3 Could + be doing:用于疑問句/否定句/肯定句中，might肯定程度稍低，表示 可 能正在”4 may /might be + doing:用于肯定句中，表示 可能正在一”e.g He must be doing his homework now.Can she

25、be still working? He cannot be still working® There is no student in the classroom. They could be playing in the playground. She may/might be writing a letter to her parents now.六.情態(tài)動詞+have done,這種結(jié)構(gòu)有兩個主要的用法。（一表示對過去發(fā)生的動作或狀態(tài)的推測或估計1 must have done表示定/準是”只用于肯定句2 may/might have done表示 大概已經(jīng)”3 Can/Could have donelfe示 可能已經(jīng)了嗎？”用于疑問句。4 can ' t/couldn ' t haveidone事情真實性不相信 不可能吧" could no也委 婉些。e.g The streets are wet. The street must have rained. They may/