高考英語情態(tài)動詞講解

1、（一）情態(tài)動詞?？键c（一） 表能力如：I am starving to death。 I can eat two bowls of rice now 。（現(xiàn)在的能力）我快餓死了，現(xiàn)在我能吃兩碗米飯。If you have a good sleep, you will be able to work out this problem。（將來的能力）如果你好好睡一覺，你將能夠解出這道題。The fire spread through the hotel very quickly but everyone was able to get out。（過去有能力做并且成功的做了某事）盡管這場大火迅速蔓延

2、到了整個賓館，但是每個人都能夠逃出去。I could have worked out the problem , but I didn't。（過去有能力做但未做）我本來可以解決這個問題，但沒有解決。（二）表推測（可能性）1 .可能性可分為客觀的可能性和具體事情實際發(fā)生的可能性兩種。所謂客觀的（理論的）可能性即并不涉及具體某事是否會發(fā)生，此種用法常?？梢哉f明人或事物的特征。情態(tài)動詞can可用于肯定句中表示客觀的（理論的）可能性，而表示具體事情實際發(fā)生的可能性時，can一般不用于肯定句。如：Accident can happen on such rainy days。這樣的多雨天氣有可能會

3、發(fā)生事故。（客觀的可能性）Peter may come with us tonight , but he isn't sure yet。彼得今晚可能和我們來，但他還沒確定。（實際可能性，不用can）2 .表示具體事情實際發(fā)生的可能性：（1）表示具體事情實際發(fā)生的可能性的層次比較詞形自定式否定式疑問式must必定，必然/will很可能，大概不會，不該會嗎would可能性比will小語氣比won't弱語氣比will弱should說話者有較大的試探性/ought to說話者有較大的試探性（含義同should）/can/、可能后可能嗎could可疑的可能/、可能語氣比can弱may或許

4、，也許，也未可知，也說不定可能不/might比may還弱比 may not還弱/（2）表不具體事情實際發(fā)生的可能性時，may, must常用于肯建句,一般不用于否te句和疑問句（may not表tk“可能不"）；can常用于否定句、疑問句或感嘆句中，表示疑惑、驚訝或不相信等意思；could既可用于肯定句,又可用于否定句、疑問句中。如：This can't/ couldn 't be done by him。（表不相信）這不可能是他做的。This may not be done by him。（表不確定）這可能不是他做的。He could be on his way h

5、ome now。 （could 不支口 may/ might 常用）他現(xiàn)在可能在回家的路上。Can this be done by him （表示疑惑、驚訝）這可能是他做的嗎Mr. Bush is on time for everything 。 How can it be that he was late for the opening ceremony （表示疑惑、 驚訝）布什先生做每件事都很按時。他怎么可能在開幕儀式上遲到呢I didn't hear the phone。I must have been aslee出（表肯定）我沒聽到電話。我肯定已經(jīng)睡著了。3. would ,

6、could , might并不一定與過去時間有關，而是表示可能性弱于他們相應的現(xiàn)在時形式。另外should也不一定與過去時間有關。如：This may/ might be done by him。（后者比前者語氣弱）這件事有可能是他干的。4. should/ ought to表推測時，表示說話者有較大的試探性。如：He ought to/ should be here on time he started early enough。他應該按時到這里一一他出發(fā)的夠早的。We should arrive before dark 。我們按說能在天黑前到達。The roads should be le

7、ss crowded today。今天路上應該不至于那么擁擠了。（三）表請求、允許、允諾1 .當對方是決策者時，你代表你（們）自己（ I, we）或代表第三者（he, she, they）向對方（you）請示或提 出建議時用： Shall I （we）Shall he/ she/theyWould/ Will you 如：Shall we begin our classShall the driver wait outsideWhen shall my father be able to leave hospitalWould you do me a favor2 . could/ might

8、/ would/ should 表委婉語氣的功能。如： Could/ Might I use your bike tomorrow morning Yes, you can/ may。（否定： No , I m afraid not。）不可以說，Yes, you could/ might。回答允許時，用 could/ might表委婉是不恰當?shù)?。如?Could I borrow your dictionary Yes, of course you can。3.當你自己（I）是決策者，給對方（you）或第三者（he, she,they）以命令、警告、允諾或威脅時，要用shall。此外，當宣布法

9、律、規(guī)定時，也要用shalL如：You shall leave the room at once, and he also shall。（ = I order you and him to leave the room at once 。） 你馬上給我滾出去！他也一樣。（說話者的意志）It has been announced that candidates shall remain in their seats until all the papers have been collected 。通知稱在所有試卷收上來之前，應試者必須留在座位那里。（規(guī)則或規(guī)定）（四）表必要性1. must常用

10、來表示必要性，意為“必須”。表示現(xiàn)在或將來必須做某事用“ must +動詞原形”；表示現(xiàn)在或將來 不必做某事時，用don't have to do sth.或don't need to do sth.或needn't do sth.；表示過去沒必要做某事時，分為以下情況：當表示過去沒必要做某事，但事實上卻做了，用needn't have done sth.；當表示過去沒必要做某事，而不涉及是否已經(jīng)做了，可用 didn't have to do sth.或 didn't need to do sth.或 It was not necessary t

11、o do sth.等。如：你昨晚本不必工作到那么晚，那對你的身體不好。 Did you work very late last night No, I didn't。I didn't need to work very late 。 您昨天晚上工作到很晚了嗎 不是很晚，我沒必要工作到很晚。2. should也可以表示必要性， 意為"（義務上）應該"。should表必要性時，在語氣上比 must （必須）弱?！皊hould +動詞原形”表示現(xiàn)在或將來應該做某事（的必要性）；“should + have +過去分詞”表示過去本該做某事（的必要性）。如：I sho

12、uld go and visit him this afternoon , but I wonder if I will be free 。今天下午我應該去看望他，但我不知道我是否有空。（表示將來的必要性）You should have come to the conference yesterdayo What was the reason for your absence你昨天應該參加那個會議。你缺席的原因的是什么（表示過去的必要性）（五）“情態(tài)動詞 + have done”用法一覽表You needn't have worded that late last night。 It

13、was harmful to your health 。（六）情態(tài)動詞 +元成式意義例句must have done“想必/準是/一定做了某事”，否te式為can t/ couldn t havedoneIt must have rained last night, for the road is quite muddy。The lights were off。They must have been asleep。can/ could have done“本來能夠”“過去可能會”Can he have gone to his aunt'sYou could have come 5 mi

14、nutesearlier ocan/ could not havedone“過去不可能”“過去沒能”I saw Mr. Wang just now 。 Hecouldn't have gone to Beijng 。may/ might havedone“也許/或許已經(jīng)”。一般只用于肯定句和否定句中 （在否定 句中表示“可能不”），不用于疑It's too late。I think he may havegone to bedoHe may not have finished the問句。用might則表示語氣更加不白心work。She might have caught a

15、cold。should/ ought to have done“本該做某事，而實際上未做”You should have come to the meeting earlier oYou ought to have done this exercise more carefully。shouldn't/ ought not to have done“本不該做而做了杲事”You shouldn 't have told her thetruth。needn't have done表小“做了本來小必去做的事”。： didn t need to do W/K 沒必要做并且實際

16、上也沒有做某事”。You needn't have taken a taxi here, for it was very near to my house 。I didn't need to clean the windows。My brother did it 。had better have done用于事后的建議，含輕微責備的 口吻，意為“要是當時做了某事 就好了 ，其否定式 had betternot have done表達相反的含義。You had better have started earlier oYou had better not have scolded

17、 her。would rather havedone表示“寧愿當時做某事”，其否定式 would rather not have done表達相反的含義，兩后部表小“后悔”之意。I would rather have taken his advice oI raised objections at the meeting , but now I would rather not have done thatowould like/ love tohave done表示過去愿意做某事，但未做成。I would love to have gone to the party last night b

18、ut I had to work extra hours to finish a report。（七）情態(tài)動詞其他用法要點1. cannot but + do sth.表示“不得不，只好”。如:2. may well 和 may as well 結構（1） “may well +動詞原形”是一種常用結構，意為“完全能，很可能“，相當于to be very likely to。如：He may well be proud of his son。他大可為兒子感到自豪。Her appearance has changed so much that youmay well not recognize

19、her。她的模樣變化太大，你很可能認不出她了。（2） “may/ might as well + 動詞原形"意為"最好，滿可以，倒不如"，相當于 had better或 to have no strong reasonnot too 如：You may as well do it at once。你最好馬上就做這件事。You may as well stay where we are。我們留在現(xiàn)在的地方倒也不錯。3. can not （或never）等否定詞與enough連用表示"再也不為過“。具體用法見形容詞、副詞專題。4. may可以用于祈使句，表示

20、祝愿。如：May we never forget each other。愿我們彼此永不相忘。May you return in safety。愿你平安歸來。5. Why/ How + should結構表示說話人對某事不能理解、感到意外、驚異等，意為"竟會" 。如：Why should you be so late today你今天來的怎么這么晚How should I know我怎么會知道（意為：我不知道。）6. must表示“偏要、硬要”做某事。如： How old are you , madam If you must know , I m twice my son&#

21、39;s ageI cannot but choose to go。我只好去。夫人，您多大了如果你硬要知道的話，我是我兒子年齡的兩倍。7. may作“可以”講時，其否定式常用mustn't"表示"禁止”;must作“必須”講時，其否定式是“needn't",表不"不必"。如： May I use your car No, you mustn't。 我可以使用你的車嗎 不，不行。（委婉的拒絕可用： Sorry , but I am using it now 。或 You ,d better noto 等） Must I w

22、ork out the problem tonight No, you needn't。 我今晚必須算出這道題嗎不，你不必。8. need和dare的用法need和dare兩者既可用作情態(tài)動詞也可用作行為動詞。作行為動詞時，有人稱和數(shù)的變化，可用于肯定句、否定句或疑問句中， 構成否定句或疑問句時要用助動詞do, does, did;作情態(tài)動詞時，沒有人稱和數(shù)的變化（dare可以有過去式dared）,直接跟動詞原形，只用于否定句和疑問句中，構成否定句和疑問句時不用助動詞。另外，dare作情態(tài)動詞時，還可用于條件句中，過去式為dared;作行為動詞時，dare用于疑問句或否定句，后面的to

23、也可省略；I dare say是習慣說法，意為“我想，大概” 。如：He needn't do thato（情態(tài)動詞）他不必那么做。He doesn't need to do it。（行為動詞）他不必做它。1 didn't know whether he dared say that to him。（情態(tài)動詞，有時態(tài)變化）我不知道他是否敢對他說那個。He didn't dare （to） do thato（行為動詞）他不敢那么做。He dared not do it。（情態(tài)動詞）他不敢做它。注意：need作行為動詞時，還可表示“需要”，后接動名詞的主動形式表示被

24、動含義（詳見“非謂語動詞專題”)。如：The floor needs sweeping。這地需要打掃了。易錯知識總結(一)易混點歸納(一)"情態(tài)動詞 + have done”結構的用法區(qū)別“情態(tài)動詞 + have done”這一考點，主要涉及以下幾個結構：1. can (could) / may (might) / must + have done多用來對過去發(fā)生的情況作出語氣強弱不同的推測。具體使用 時請注意以下幾點：(1) can表推測，一般用于疑問句和否定句，極少用于肯定句。如： Can she have gone to school No, she can ;t have g

25、one to school o I saw her just now o(2) may表推測，一般不用于疑問句；疑問句中該用 can, could或might o如：How could he have forgotten such an important thing (不用 may)Might you have met him somewhere (不用 may)(3) must表推測，一般不用于否定句；否定句中應用 can或could。如：誤： We mustn't have met before。正： We can't have met before o(4) 表推測時c

26、ould , may, might用于肯定句語氣較弱；must用于肯定句語氣很強；may, might用于否定句語氣較弱；can, could用于否定句語氣很強。如：He could/ may/ might have gone to school。他可能上學去了。He must have gone to school。他肯定是上學去了。He may/ might not have gone to school。他也許沒去上學。He can V couldn 't have gone to school o他肯定沒去上學。,在否定句中表示“已做了不該做的事”2. should/ ough

27、t to + have done在肯定句中表示“該做的事情沒有做”通常用來表示一種義務、自責或提出委婉的批評。如：You should/ ought to have come here earlier。You shouldn't/ ought not to have told her the newsoI should have done my homework last night , but I watched TV instead 。3. needn't + have done可用來表示“已做了不必做的事”。如：There is no school today。 You

28、needn't have come。4. could + have done可用來表示沒做某事的遺憾。如：She came here on foot, but she could have come by bus。5. could/ might + have done也可用來表示委婉的批評。如：You could have come 5 minutes earlier oYou might at least have written me a letter o6. 在反義疑問句中，表推測的情態(tài)動詞不出現(xiàn)在簡短問句部分。句中有過去時間狀語的，問句部分用過去時, 否則，用現(xiàn)在完成時。如：He must have been there yesterday , wasn't heHe must have been there, hasn't heHe must have been there yesterday , was heHe must have been there, has he（二）情態(tài)動詞后面接進行時的情況1. can后面接進行時表示可能正在發(fā)生的動作。如：What can she be doing at this moment這個時候她會在做什么呢You can't be telling us the trutho你不可能在對