情態(tài)動詞用法歸納.doc

情態(tài)動詞用法歸納情態(tài)動詞有can (could), may (might), must, have to, shall (should, will (would), dare (dared), need (needed), ought to等。 情態(tài)動詞無人稱和數(shù)的變化；不能單獨使用，必須與其后的動詞原形構(gòu)成謂語一、 can, could1) 表示能力（體力、知識、技能）。Can you lift this heavy box?（體力）Mary can speak three languages.（知識）Can you skate?（技能）此時可用be able to代替。Can只有一般現(xiàn)在時和一般過去式；而be able to則有更多的時態(tài)。Ill not be able to come this afternoon.當(dāng)表示“經(jīng)過努力才得以做成功某事”時應(yīng)用be able to，不能用Can。如：He was able to go to the party yesterday evening in spite of the heavy rain.2) 表示請求和允許。-Can I go now?- Yes, you can. / No, you cant.此時可與may互換。在疑問句中還可用could,might代替，不是過去式，只是語氣更委婉，不能用于肯定句和答語中。- Could I come to see you tomorrow?- Yes, you can. ( No, Im afraid not. )3) 表示客觀可能性（客觀原因形成的能力）。Theyve changed the timetable, so we can go by bus instead.This hall can hold 500 people at least.4) 表示推測（驚訝、懷疑、不相信的態(tài)度），用于疑問句、否定句和感嘆句中。Can this be true?This cant be done by him.How can this be true?二、 may, might1) 表示請求和允許。might比 may語氣更委婉，而不是過去式。否定回答時可用cant或mustnt，表示“不可以，禁止”。-Might/ May I smoke in this room?- No, you mustnt.- May/Might I take this book out of the room?- Yes, you can. (No, you cant / mustnt. )用May I.？征徇對方許可時比較正式和客氣，而用Can I.？在口語中更常見。2）用于祈使句，表示祝愿。May you succeed!3) 表示推測、可能性（不用于疑問句）。might不是過去式，它所表示的可能性比may小。1He may /might be very busy now.2Your mother may /might not know the truth.三、 must, have to1) 表示必須、必要。You must come in time.在回答引出的問句時，如果是否定的，不能用mustnt（禁止，不準(zhǔn)），而用neednt, dont have to（不必）.- Must we hand in our exercise books today?- Yes, you must.- No, you dont have to / you neednt.2) must是說話人的主觀看法， 而have to則強(qiáng)調(diào)客觀需要。Must只有一般現(xiàn)在時， have to 有更多的時態(tài)形式。1 he play isnt interesting, I really must go now.2 I had to work when I was your age.3) 表示推測、可能性（只用于肯定的陳述句）1 Youre Toms good friend, so you must know what he likes best.2 Your mother must be waiting for you now.四、 dare, need1) dare作情態(tài)動詞用時, 常用于疑問句、否定句和條件從句中, 過去式形式為dared。1 How dare you say Im unfair?2 He darent speak English before such a crowd, dare he?3 If we dared not go there that day， we couldnt get the beautiful flowers.2) need 作情態(tài)動詞用時, 常用于疑問句、否定句。在肯定句中一般用must, have to, ought to, should代替。1You neednt come so early.2. - Need I finish the work today?- Yes, you must. / No, you neednt.3) dare和 need作實義動詞用時， 有人稱、時態(tài)和數(shù)的變化。在肯定句中，dare后面常接帶to的不定式。在疑問句和否定句中，dare后面可接帶to或不帶to的不定式。而need后面只能接帶to的不定式。1. I dare to swim across this river.2. He doesnt dare (to) answer.3. He needs to finish his homework today.五、 shall, should1) shall 用于第一人稱，征求對方的意見。What shall we do this evening?2) shall 用于第二、三人稱，表示說話人給對方的命令、警告、允諾或威脅。1. You shall fail if you dont work hard.(警告)2. He shall have the book when I finish it.(允諾)3. He shall be punished.(威脅)六、 will, would1) 表示請求、建議等，would更委婉。Will / Would you pass me the ball, please?2) 表示意志、愿望和決心。1. I will never do that again.2. They asked him if he would go abroad.3) would表示過去反復(fù)發(fā)生的動作或某種傾向。would表示過去習(xí)慣時比used to正式，且沒有“現(xiàn)已無此習(xí)慣”的含義。1. During the vacation, he would visit me every other day.2. The wound would not heal.4) 表示估計和猜想。It would be about ten oclock when she left home.七、 should, ought to1) should, ought to表示“應(yīng)該”，ought to表示義務(wù)或責(zé)任，比should語氣重。1. I should help her because she is in trouble.2. You ought to take care of the baby.2) 表示勸告、建議和命令。should, ought to可通用，但在疑問句中常用should。1. You should / ought to go to class right away.2. Should I open the window?3) 表示推測should , ought to (客觀推測), must(主觀推測)。1.He must be home by now. (斷定他已到家)2.He ought to/should be home by now.(不太肯定)3. This is where the oil must be.(直爽)4. This is where the oil ought to/should be.(含蓄)從高考題看情態(tài)動詞的用法 最近幾年高考試題中常常借助語境來考查情態(tài)動詞的基本用法及其區(qū)別，因此在平時學(xué)習(xí)時準(zhǔn)確理解和掌握情態(tài)動詞的基本用法十分重要。情態(tài)動詞的用法復(fù)雜多變，在高考試題中，命題者常常利用語境和句子之間意義上的細(xì)微差別來考查學(xué)生對情態(tài)動詞的理解和掌握。對于情態(tài)動詞，除了要求考生能夠準(zhǔn)確掌握它們的基本用法外，還要充分利用高考試題所設(shè)置的語境來分析句子之間所體現(xiàn)的特殊關(guān)系。下面就近幾年來高考試題中出現(xiàn)的情態(tài)動詞的考點進(jìn)行歸納分析，以便同學(xué)們復(fù)習(xí)掌握。一、用“情態(tài)動詞have done”結(jié)構(gòu)表示對過去動作的推測，高考試題中常用過去時態(tài)或過去的時間狀語給以暗示。情態(tài)動詞的這一用法可以用 “對立統(tǒng)一”來概括。1當(dāng)試題的前句和后句在動作和意義上相互補充說明，且整個句意在動作和時間上是一個整體時，我們可用“統(tǒng)一”關(guān)系來解決這樣的試題。常見的結(jié)構(gòu)有：must have done： 表示對過去動作的肯定推測，常譯作“一定做了”，只能用于肯定句中。其否定形式為cantcouldnt have done 疑問式為CanCould.have done？。could might have done：表示對過去發(fā)生的動作的可能性推測，常譯作“可能做了”。如：1) Sorry Im late I have turned off the alarm clock and gone back to sleep again (北京 2000春)A might B should C can D will該題前句說明了結(jié)果，后句接著說出了產(chǎn)生這種結(jié)果的可能性，對前句進(jìn)行補充說明。分析選項可知本題應(yīng)選A。2) My sister met him at the Grand Theater yesterday afternoon, so he your lecture (上海 2000)A couldnt have attendedB neednt have attendedC mustnt have attendedD shouldnt have attended該題前句敘說一個客觀事實，后句對前句進(jìn)行補充說明，分析選項可知C是錯誤的 而B、D兩項不符合題意。故本題選A。又如：Jack yet, otherwise he would have telephoned me (上海97)A mustnt have arrivedB shouldnt have arrivedC cant have arrivedD need not have arrived （C）2當(dāng)試題的前后句在動作和意義上構(gòu)成轉(zhuǎn)折關(guān)系時，常借助“but, however, instead”等詞來表示過去的動作與客觀事實不符，這時我們就可以用“對立”關(guān)系來解決這樣的試題。這種結(jié)構(gòu)常見的有：should have done ought to have done：表示過去本應(yīng)該做某事而實際上沒有做。should not have done ought not to have done：表示過去本不應(yīng)該做某事但事實上卻做了。need have done：表示過去本來有必要去做某事，但事實上沒有做。need not have done：表示過去本來沒有必要做某事，但事實上卻做了。如：3) I was really anxious about you You home without a word (NMET2001)A mustnt leave B shouldnt have leftC couldnt have left D neednt leave分析該題前后句之間的關(guān)系和語氣可知，事實上是 “本不應(yīng)該離家出走卻走了”，故本題選B。4) I told Sally how to get here, but perhaps I for her (NMET94)A had to write it outB must have written it outC should have written it outD ought to write it out由句中的連詞but可知前后句之間是對立關(guān)系，分析題意可知本題應(yīng)選C。二、考查情態(tài)動詞基本用法之間的比較和辨析。最近幾年高考試題中常借助具體的語境來考查考生對那些最常見的情態(tài)動詞的基本用法的理解和掌握，因此在做這樣的試題時應(yīng)認(rèn)真分析語境中所含的實際意義，并結(jié)合情態(tài)動詞的基本含義和用法做出正確的選擇。6) I hear youve got a set of valuable Australian coins _ I have look?Yes, certainly (北京2002春)A Do B May C Shall D Should分析語境可知這是在征求對方的許可，may表示“允許、可以”，語氣比較委婉 shall常用于第一、三人稱作主語的疑問句中,表示征求對方意見和指示，如果此空用shall，則意為“要（我）看一下嗎？”，不符合上下文意思。故本題選B。7) Mr Bush is on time for everything How it be that he was late for the opening ceremony？ (上海2001春)A can B should C may D mustmust be 表示肯定的猜測，只能用于肯定句中，由題意可知本題應(yīng)選A。8) Are you coming to Jeffs party?Im not sure I go to the concert instead (NMET2000)A must B would C should D might由題意和下句中的 “Im not sure” 可知這段對話中存在一種可能性推測，might可以用來表示一種比較委婉的可能性判斷，故本題選D。9) Johnny, you play with the knife, you hurt yourself (NMET96)A wont; cant B mustnt; mayC shouldnt; must D cant; shouldntmustnt 表示“不可以；禁止”，分析題意可知第二個空表示某種可能性，故本題選B。10) Will you stay for lunch？Sorr