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專題09 情態(tài)動詞和虛擬語氣 易錯點1 情態(tài)動詞的誤用 1. Some people who don’t like to talk much are not necessarily shy; they _______________ just be quiet people. A. must B. may C. should D. would 【錯因分析】考生容易誤選C項，認(rèn)為是＂一定是＂，實際上這里表示可能性。 【參考答案】B may/might接動詞原形時表示對現(xiàn)在情況的推測，意思是＂可能＂。 She thought it might be wise to try her luck here. 她認(rèn)為在這兒碰碰運氣也許不錯。 2. —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 【錯因分析】考生容易誤選A項，認(rèn)為這里要用will表示將來或意愿。shall在本句中用于第三人稱，表示警告和禁止；will表示現(xiàn)在的意志、愿望等，意為＂要，希望＂；may表示許可，或用于請求許可，意為＂可，可以＂；must意為＂必須，要，應(yīng)當(dāng)＂。 【試題解析】句意：——那邊的那個標(biāo)志說的什么？——任何人都不準(zhǔn)在這個區(qū)域吸煙、或攜帶點著的香煙、雪茄或煙斗。根據(jù)語境可知這里表示警告和禁止，因此要用should。 【參考答案】C shall用作情態(tài)動詞主要有以下兩個用法： （1）用于第一、三人稱的疑問句，表示征求對方意見。 Shall I help you? 要不要我?guī)湍悖? Shall I open the window? 要我把窗子打開嗎？ Shall she go to the concert with us this evening? 她要和我們一起去音樂會嗎？ （2）用于陳述句中表示允諾、告誡、警告、威脅、命令、規(guī)定、必然性等（可用于各類人稱）。 You shall suffer for this. 你會為此事吃苦頭的。（表威脅） Each petitor shall wear a number. 每個參賽者要戴一個號碼。（表規(guī)定） You shall hear everything as soon as you e. 你一來就可以聽到所有的情況。（表允諾） You shall go to the front at once. 你馬上到前線去。（表命令） Don’t worry. You shall get the answer this very afternoon. 不要著急，你今天下午晚些時候可以得到答案。（表允諾） He shall be sorry one day. I tell you. 我告訴你，他早晚會后悔的。（表警告） Nothing shall stop us from fighting against pollution. 什么也阻止不了我們與污染作斗爭。（表決心） 1.【2018北京卷單項填空】In today’s information age, the loss of data _________ cause serious problems for a pany. A. need B. should C. can D. must 【答案】C 2. I think the work ____________ be pleted ahead of time. 【解析】句意：我認(rèn)為這項工作可以提前完成。由句意可知這里表示說話人的一種看法，故填can。 【答案】can 【名師點睛】此題有些考生可能會認(rèn)為這里是要求工作＂必須＂提前完成而誤填must，因此在做此類題時，一定要結(jié)合語境，仔細(xì)推敲語境暗含的意思，從而提高做題的正確率。 3. —It’s the office! So you ____________ know eating is not allowed here. —Oh, sorry. A. must B. will C. may D. need 【答案】A 【名師點睛】must常用來表示禁止、命令，這時主要用于否定句中。 You must not speak ill of others. 你一定不要說別人的壞話。 You must not go there. 你不準(zhǔn)去那兒。 情態(tài)動詞的基本用法 （一）情態(tài)動詞的特點 情態(tài)動詞，在英文中主要用來表示說話人的看法、態(tài)度等。它很接近中文里的能愿動詞。從用法上來說，它有這樣幾個特點： 1. 各個情態(tài)動詞自身都有一定的詞義。 2. 情態(tài)動詞不能在句中獨立擔(dān)當(dāng)謂語。 3. 情態(tài)動詞在句中不受任何人稱、性、數(shù)變化的影響。 4. 情態(tài)動詞后接的不定式（除ought外）都不帶to，即接動詞原形。 （二）常用情態(tài)動詞的基本用法 英文中的情態(tài)動詞主要有：can, could; may, might; must; ought; need; dare, dared，另外，shall, will, should, would在一定的場合也可用作情態(tài)動詞。 He can speak five languages. 他會說五種語言。 She must have arrived home by now. 現(xiàn)在她準(zhǔn)到家了。 We should study hard for our motherland. 我們應(yīng)該為祖國而努力學(xué)習(xí)。 They needn’t be in such a hurry for there is enough time for them. 他們還有足夠的時間，用不著這么慌張。 1. can, could 能，會 could可以看作是can的過去式，這兩個詞除了時態(tài)不相同外，在表達(dá)意思的許多方面是相同的。當(dāng)然could也有自己獨特的用法。 （1）表示腦力或體力上的能力 Nobody can stop the development of science. 誰也無法阻止科學(xué)的發(fā)展。 She can sing that song in English. 她能用英文唱那歌。 He can submerge to a depth of about twenty meters. 他能潛入約二十米深的水中。 He could hardly support his family before he found the new job. 他在找到那份新工作前幾乎無法養(yǎng)家。 I could not understand the lecture on the puter given by Mr. Smith. 我聽不懂史密斯先生作的那個關(guān)于計算機(jī)的講座。 （2）表示客觀上的可能性 You can borrow this useful book from the library. 你可以從圖書館借到這種有用的書。 A more suitable person than him for the job cannot be found. 不可能找到比他更適合這份工作的人了。 Now people can skate on the lake. 現(xiàn)在人們可以在湖上滑冰了。 When the storm stopped, the plane could take off. 當(dāng)風(fēng)暴停下來時，飛機(jī)可以起飛了。 （3）表示主觀上的允許 Can I ask you some questions about it? 我可以問你有關(guān)這件事的幾個問題嗎？ You cannot leave here till I e back. 直到我回來你才能離開。 Such kind of thing can’t happen anymore later. 這類事以后不準(zhǔn)再發(fā)生了。 Can you tell me how to get to the airport? 你能告訴我怎么去機(jī)場嗎？ Could you tell me how to get to the airport? 您能告訴我怎么去機(jī)場嗎？ Could I be forgiven my negligence? 請原諒我的疏忽，行嗎？ （4）表示猜測、懷疑或驚詫（用于否定句、疑問句或感嘆句中） How can / could you be here? 你怎么會在這兒？ She couldn’t / can’t be so stupid to do that. 她不可能蠢得去做那種事吧。 He couldn’t / can’t be over seventy. 他不可能有七十多歲了。 Where could / can the boy be now? 那孩子現(xiàn)在能在哪兒呢？ 另外，could還常用于表示較客氣委婉的看法、提問及用于虛擬語氣的結(jié)構(gòu)中。這時候，could就不可以看作是can的過去式了。而是could自己獨特的用法。 Could you speak a little slowly? 您能稍微說慢一點兒嗎？ I could e earlier if asked. 如果要讓我早一點來，我可以來早一點。 I’m afraid that we couldn’t give you any definite answer at this moment. 恐怕我們這時候還無法給予你任何確切的答復(fù)。 We would appreciate it if you could offer us any help. 如果您能為我們提供幫助的話，我們將不甚感激。 You could have done better if you had worked harder at it. 如果你再加把勁，你本來可以做得更好一些的。 2. may, might 或許，可能，可以 might可以看作是may的過去式，這兩個詞除了時態(tài)不相同外，在表達(dá)意思的許多方面是相近的。當(dāng)然may 和might又都有一些各自不同的獨特用法。 （1）可能性 I may be busy from tomorrow on. 從明天起我可能會忙起來。 I wondered if they might agree with the idea. 我想知道他們是否會同意這種想法。 She thought it might be wise to try her luck here. 她認(rèn)為在這兒碰碰運氣也不錯。 You may catch sight of the sunrise from here when you get up before 5 in the morning. 你在早晨五點鐘以前起來，或許能從這兒看到日出。 （2）表示允許 May I e in? 我可以進(jìn)來嗎？ I’d like to have a smoke here if I may. 如果可以的話我想在這兒抽一支煙。 The librarian told her that she might return the book to the library in three days. 圖書館理員告訴她說，她可以在三天后還那本書。 At the press conference, a news reporter asked the chairman if she might trouble him with a question about Taiwan issue. 在記者招待會上，一位新聞記者問大會主席她是否能提一個有關(guān)臺灣問題方面的問題。 （3）may可以用來表示祝愿，也常用于表示目的或讓步的狀語從句中： May that day e soon. 但愿那天早日到來。 May you succeed in winning the first prize in the game. 祝愿你比賽奪冠成功。 May you continue in your efforts and achieve greater successes. 祝愿你繼續(xù)努力并取得更大的成功。 （4）might也常用于表示目的等狀語從句中，或用于虛擬語氣的結(jié)構(gòu)中： I could not convince him, try as I might. 我無論用什么樣的辦法也不能說服他。 He died so that the others might live. 為了其他的人能活下去，他自己犧牲了。 One error in calculation might ruin the whole project. 計算中出一點錯就可能毀掉整個工程。 They left off earlier on that day so that they might catch the first train. 那天，他們?yōu)榱粟s上頭班車動身早一些。 If you had made better use of your time, you might have learned more. 假若你將自己的時間利用得更好一些，你本可以學(xué)到更多東西的。 ★ 注意：在回答以may引導(dǎo)的問句時，一般說來避免使用may，以免顯得太嚴(yán)厲、或不太客氣，而改用其他方式。 —May I e in? 我可以進(jìn)來嗎？ —Yes, please. / Sure. / Certainly. 請進(jìn)。 —Please don’t. 請不要進(jìn)來。 —No , you mustn’t. 不行。 3. must 應(yīng)該，必須，一定 （1）表示出于職責(zé)、義務(wù)該做某事 We must protect people’s rights. 我們應(yīng)該保護(hù)人民的利益。 Everyone must be loyal to his motherland. 每個人都應(yīng)該忠于自己的祖國。 You must serve the people when you grow up. 你們長大成人后應(yīng)該服務(wù)于人民。 Students must work hard at their study. 學(xué)生應(yīng)該努力學(xué)習(xí)。 （2）表示出于主觀意識而必須要做某事 We must speed up the pace of our economic reform. 我們必須加速經(jīng)濟(jì)改革的步伐。 We must keep steps to the scientific development. 我們一定要與科學(xué)的發(fā)展保持步調(diào)一致。 You must hurry up or you’ll be late. 你必須得快點兒，不然會遲到的。 ★ 注意：在這種用法中must表示出于主觀意識而必須要做某事；have to卻表示由于某種客觀原因而不得不做某事。除此以外，have to自身有時態(tài)的變化形式。 I have to go now for I’ve got a meeting 15 minutes later. 我現(xiàn)在必須要走了，因為我15分鐘后有個會要開。 He has to be back home by five to fetch his son from kindergarten. 他必須在五點鐘前回家去幼兒園接他的兒子。 Jenny had to tidy up the room before her mother came back. 珍尼不得不在她媽媽回家以前將房間整理好。 ★ 注意：在這種用法中，回答以must引導(dǎo)的問句時，若是否定答復(fù)，不可以用mustn’t 而需要用needn’t 或是don’t have to，因為mustn’t意思是＂絕不能、一定不要＂，而沒有＂不必＂的意思。 —Must we hand in our exercises today? 我們今天必須交作業(yè)嗎？ —Yes, you must. 是的，必須交。 —No, you needn’t（or, you don’t have to ）. 不，不必今天交。 （3）表示禁止（用于否定句） You must not speak ill of others. 你一定不要說別人的壞話。 Cars must not park here. 這里禁止停車。 Smoking must not allow in the office. 嚴(yán)禁在辦公室吸煙。 You mustn’t talk to girls like that. 你絕不能那樣對女孩子說話。 （4）表示猜測、推測，must常用于肯定句中表示猜測。對現(xiàn)在或未來的事進(jìn)行猜測時，后接動詞原形；對已經(jīng)發(fā)生的事進(jìn)行猜測時，后接have + 過去分詞。 You must be tired after working so long. 你工作這么長時間，肯定累了吧。 It must be that naughty boy crying outside. 肯定是那個調(diào)皮的孩子在外面大叫。 It must have rained last night for it is so wet outside. 外面這么濕，昨晚肯定下雨了。 The idea must be accepted by the society sooner or later. 這種想法肯定遲早會被社會所接受的。 I didn’t see you in class yesterday. You must have been absent. 我昨天上課沒見著你，你肯定沒有來。 4. ought 應(yīng)該（后接帶to的不定式構(gòu)成謂語動詞） （1）表示出于職責(zé)、義務(wù)該做某事 You ought not to be so careless in your work. 你不應(yīng)該在工作上如此粗心大意。 We ought to study hard for the sake of our motherland. 我們應(yīng)該為了我們的祖國而努力學(xué)習(xí)。 His doctor said to him that he oughtn’t to smoke so much. 他的醫(yī)生說他不應(yīng)該抽這么多煙。 Oughtn’t you to give us a chance to try? 你難道不應(yīng)該給我們一個嘗試的機(jī)會嗎？ （2）表示極有可能發(fā)生某事 As an auto repairman, Dick ought to know what is wrong with the car. 作為一個汽車修理工，狄克應(yīng)該知道這部車的毛病所在。 If we set off right now, we ought to be able to get there in time. 如果我們馬上出發(fā)，我們應(yīng)當(dāng)能夠按時到達(dá)那里。 Tomorrow ought to be a nice day for we have such a fine sunset today. 今天有這么好的晚霞，明天準(zhǔn)是個晴天。 5. need需要（用于否定句和疑問句） There are still one and a half hours to go, we needn’t be in such a hurry. 還有一個半小時，我們無需如此慌張。 I hardly need say how much we missed you. 不用說我們是多么地想念你。 Need you go so soon? 你需要這么早就去嗎？ You need have no anxiety on my account. 你不必為我而著急。 6. dare, dared敢（用于否定句、疑問句和疑問句） Dare you stay here alone in the night? 你敢在夜里待在這兒嗎？ Nobody dared mention that matter. 沒有人敢提那件事。 How dared you say that to her? 你怎么敢對她說那件事？ Even if you dare do it, I won’t allow you to because it’s too dangerous. 即使你敢做，我也會讓你做那件事，因為太危險了 7. shall用作情態(tài)動詞時，適用于第二人稱和第三人稱。 主要表示下面幾層意思： （1）許諾 You shall hear everything directly you e. 你一來就可以聽到一切了。 ＂Whatever you want you shall have, ＂said the Fairy. 仙女說：＂你想得到什么，你就可以有什么。＂ I don’t want to be hard on your daughter; she shan’t be pressed. 我不想對你女兒太嚴(yán)厲，她不會受壓制。 I promise that you shall see her again before long. 我保證你不久就能再見到她。 （2）命令 You shall e to my office immediately. 你必須馬上來我的辦公室。 She shall not stay in my garden. 她不可以待在我的花園里。 He shall not e into my study. 不許他進(jìn)我的書房。 You shall do as you are told. 按告訴你的那么做。 （3）決心（表示某事一定會發(fā)生） That day shall e. 那一天一定會到來。 It has been decided that he shall be given the job. 已經(jīng)決定讓他做那份工作了。 This law shall e into effect on January 1st 2001. 這個法律于2001年1月1日生效。 （4）規(guī)定 Each petitor shall wear a number. 每個參賽者要佩戴一個數(shù)字標(biāo)。 The renter shall keep the house in a neat and orderly state. 租賃者要保持房屋整潔有序。 The supplier shall make shipment before October and the purchaser shall make payment within 15 days after　　receipt of the goods. 賣方十月以前裝運，買方在收到貨物后十五天內(nèi)付款。 8. should用作情態(tài)動詞時，有時表示具體的意思，有時沒有意義。主要用于下面幾個方面： （1）表示出于職責(zé)、義務(wù)該做某事 You shouldn’t e to such a decision hastily. 你不應(yīng)該匆忙做出這么一個決定。 You should write to your parents at least once a month. 你應(yīng)該至少每月給你父母親寫一封信。 We should read English aloud every morning. 我們應(yīng)該每天早晨朗讀英文。 They should do it for their own good. 為了他們自己利益他們應(yīng)該做這件事。 （2）表示對某種情況的估計 She shouldn’t be out in such an early morning. 她不會這么一大早就出去了吧。 This book should be published in two months at most. 這本書最多兩個月后就會出版的。 The effect of the tax should be felt in higher prices. 人們可能會從各種上漲的物價中感覺到這種稅的影響的。 The event should lead them to a even worse economic crisis. 這次事件可能會將他們引向更嚴(yán)重的經(jīng)濟(jì)危機(jī)。 （3）表示驚訝、失望等情緒 I think it is dreadful that anyone should be so miserable. 我認(rèn)為，竟然每個人都如此傷心就太糟糕了。 Why should I pay him for nothing? 我干嗎要白白付給他錢？ It seems so unfair that this should happen to me. 這件事竟然發(fā)生在我身上，似乎太不公平了。 It’s strange that it should be so cold today. 奇怪，今天怎么會這么冷。 （4）用于某些從句中表示虛擬語氣 The doctor insisted that the girl should be hospitalized. 大夫堅持認(rèn)為那個女孩要住院治療。 She stood away so that he should enter the room first. 她讓到一邊，好讓他第一個進(jìn)入房間。 I’ll write it down lest I should forget it. 我將它記下以免遺忘。 Take an umbrella with you in case it should rain. 帶上雨傘，以防下雨。 9. will, would would可以看作是will的過去式，這兩個詞除了時態(tài)不相同外，在表達(dá)意思的許多方面是相近的。當(dāng)然will 和would又都有一些各自不同的獨特用法。 （1）用于第二人稱疑問句，表示請求（在這種用法中would使語氣更為客氣、委婉） Will you tell her that I’ll be back in twenty minutes? 請告訴她我二十分鐘后回來，好嗎？ If you want help, just let me know, will you? 你需要幫助就告訴我，好嗎？ Would you tell me how to get to the shopping center? 您能告訴我怎么去購物中心嗎？ Won’t you e in and have a little whisky? 你要不要進(jìn)來喝一點兒威士忌？（或是：你進(jìn)來喝一點兒威士忌，好嗎？） （2）用于表示愿望 Go where you will. 去你想去的地方吧。 I will pay you at the rate you ask. 我會按你要的利率付給你錢的。 He wouldn’t let the doctor take his blood pressure. 他不愿意讓大夫給他量血壓。 They had to obey whether they would or not. 不管他們愿意與否，他們必須要遵從。 （3）表示習(xí)慣、傾向（可譯成＂總是會、老是，等＂ ） Sometimes the cat will lie there all afternoon. 有時侯，那只貓會整個下午都躺在那兒。 Oil and water will not mix. 油和水不能混合。 He would sit there for hours, doing nothing at all. 他總是在那兒一坐就是幾個小時，什么都不干。 （4）表示猜測（可譯成＂一定是……、想必……，等＂ ） This will be the house you’re looking for. 這想必就是你要找的房子吧。 He will have gone back to New Zealand. 他一定是回新西蘭去了。 That would be in 1999, I think. 那大概是在1999年吧。 （5）will用于表示決心（可譯成＂一定要，決心＂等 ） We will never talk about that subject again. 我們決不會再談?wù)撨@個話題了。 I will make this puter work even if I have to stay up all night. 我即使整晚不睡覺也一定要讓這臺計算機(jī)工作起來。 （6）would常用于虛擬條件句，表示與事實相反或不太可能實現(xiàn)的情況 But for your help we would have been late. 要不是你幫忙我們就遲到了。 Well, I wouldn’t worry about it. It won’t do me any good. 好了，我不會擔(dān)心那件事的，因為它不會給我?guī)硎裁春锰帯? 易錯點2 混淆＂情態(tài)動詞+have done＂各種句式的不同含義 1. —Where is my dictionary? I remember I put it here yesterday. —You ____________ it in the wrong place. A.must put B.should have put C.might put D.might have put 【錯因分析】考生容易誤選A項，原因是受漢語表達(dá)習(xí)慣的影響，認(rèn)為＂你一定是把它放錯地方了＂。根據(jù)前面的語境可判斷出，本題考查情態(tài)動詞表推測的用法。所以要用might have done。should have done表示＂(過去)本來應(yīng)該做某事＂。must意為＂一定＂，是肯定的推測，與所提供的情景矛盾。might put表示現(xiàn)在發(fā)生的事。 【參考答案】D 情態(tài)動詞＋have done 用法 must have done 一定做過某事，其否定形式為can’t/couldn’t have done can/could have done 本來能夠做某事但卻未做 可能做過某事 can’t/couldn’t have done 不可能做過某事 may/might have done 或許/可能做過某事 should/ought to have done 本該做但卻未做，其否定形式表示本不該做但卻做了 needn’t have done 做了本沒有必要做的事情 1.【2018天津卷單項填空】 I cant find my purse. I___________ it in the supermarket yesterday, but Im not sure. A. should leave B. must have left C. might leave D. could have left 【答案】D 2.That car nearly hit me; I ______________. A. might be killed C. may be killed B. might have been killed D. may been killed 【解析】句意：那輛小轎車差點撞到了我，我差點被撞死。被撞死是過去可能發(fā)生而實際并沒有發(fā)生的事情，因此要用might have been killed。 【答案】B 【名師點睛】may/might have + 過去分詞表示對過去已經(jīng)發(fā)生的事進(jìn)行推測判斷，一般只用于肯定句或否定句中（疑問句中用can或could），may/might的意思是＂可能，也許＂，may/might的意思是＂可能不（沒有）＂。 Nobody stopped him; he might have been a passenger’s child. 沒人制止他，他或許是一個旅客的孩子。 It’s no use going to his house. He may not have gone home; he may have gone somewhere else. 去他家沒有用，他可能沒有回家，可能去別的地方了。 注意：might have + 過去分詞可用來表示過去可能發(fā)生而沒有發(fā)生的事情。 You were so careless that day. You might have made a bad mistake. 那天你太粗心了，你有可能犯錯誤的。（事實上并沒有犯錯） 1.＂must have done＂ 表示對過去事情的肯定推測，譯成＂一定做過某事＂，該結(jié)構(gòu)只用于肯定句。 It must have rained last night, for the ground is wet. 昨晚一定下雨了，因為地面還是濕的。 You must have been mad to speak to the servant. 你和仆人說話，一定是發(fā)瘋了。 2.＂can’t have done＂ 表示對過去事情的否定推測，譯成＂不可能做過某事＂。 Mr Smith can’t have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我剛才還在圖書館見過他。 Mary can’t have stolen your money. She has gone home. 瑪麗不可能偷你的錢，她回家去了。 3.＂can have done＂ 表示對過去行為的懷疑，用于疑問句，譯成＂可能做過……嗎？＂。 There is no light in the room. Can they have gone out? 屋里沒有燈，他們可能出去了嗎？ There is nowhere to find them. Where can they have gone? 到處找不到他們，他們可能到什么地方去呢？ 4.＂could have done＂ 是虛擬語氣，表示對過去事情的假設(shè)，意思是本來能夠做某事而沒有做。 He could have passed the exam, but he was too careless. 本來他能夠通過考試，但是他太粗心。 5.＂may have done＂ 表示對發(fā)生過的事情的推測，意思是＂可能已經(jīng)＂或＂也許已經(jīng)＂，用于肯定句中。 —What has happened to George? 喬治發(fā)生了什么事？ —I don’t know. He may have got lost. 我不知道，他可能迷路了。 6.＂might have done＂ 表示對過去事情的推測，might與may意思相同，但可能性更小。多用于虛擬語氣結(jié)構(gòu)中。 She might have achieved greater progress, if you had given her more chances. 如果你多給她點機(jī)會，她可能已經(jīng)取得了更大的成績。 7.＂would have done＂ 虛擬語氣，表示對過去事情的假設(shè)，意思是＂本來會……＂。 I would have told you all about the boy’s story, but you didn’t ask me. 我本來會告訴你這個小男孩的故事，但是你沒有問我。 8.＂should have done＂ 意思是＂本來應(yīng)該做某事，而實際沒做＂。＂shouldn’t+have+done＂表示本來不應(yīng)該做某事，而實際做了。含有指責(zé)對方或自責(zé)的含義。 Tom, you are too lazy. The work should have been finished yesterday. 湯姆，你太懶惰了，這項工作本來應(yīng)該昨天就做完的。 Look, Tom is crying. I shouldn’t have been so harsh on him. 看，湯姆哭了，我本不應(yīng)該對他如此嚴(yán)厲的。 9.＂ought to have done＂ 表示過去應(yīng)該做而實際并沒有做，譯成＂理應(yīng)做……＂，往往表示遺憾。與＂should have done＂用法基本一樣。 I ought to have gone home last Sunday. 我理應(yīng)上星期日回家。 You ought not to have given him more help. 你不應(yīng)該幫助他那么多。 10.＂need have done＂ 表示本來需要做某事而實際沒有做。＂needn’t have done＂則表示＂本來不需要做某事而實際做了＂ I needn’t have bought so much wine — only five people came. 我本來沒有必要買這么多酒，只來了五個人。 He need have hurried to the station. In that case, he wouldn’t have missed the train. 他本來需要快點去車站的，那樣的話，他就不會誤了火車。 易錯點3 虛擬語氣時態(tài)的誤用 1. I _________ through that bitter period without your generous help. 【錯因分析】此題考生容易誤認(rèn)為空格處表示現(xiàn)在的情況，用＂would+動詞原形＂，從而填成了wouldn’t go，實際上這是對過去的假設(shè)。 【試題解析】句意：如果沒有你的慷慨幫助我不能度過那段艱難的時期。度過那段艱難的時期是過去發(fā)生的事情，因此這里是對過去發(fā)生的事情的假設(shè)，又因這里表示否定意義，因此要用couldn’t have done。 【參考答案】couldn’t have gone 虛擬語氣中，主句用＂would / might / could + 動詞原形＂表示現(xiàn)在或?qū)淼那闆r，用＂would / might / could + have + 過去分詞＂表示過去的情況。 1.【2018北京卷單項填空】They might have found a better hotel if they _________ a few more kilometers. A. drove B. would drive C. were to drive D. had driven 【答案】D 2. But for their help, we _______ the program in time. A. cannot finish B. will not finish C. had not finished D. could not have finished 【試題解析】句意：要不是他們的幫助，我們不會按時完成這個項目?？忌菀渍`選C項，原因是沒有注意到but for their help這一含蓄條件。由語境可知，這里表示與過去的事實相反，所以主句應(yīng)該用would /could / might / should + have done結(jié)構(gòu)。 【答案】D 【名師點睛】 （1）有些句子中，沒有任何表示虛擬語氣的詞、短語或從句，但仍要用虛擬語氣。這時，要么是省略了表示虛擬語氣的部分，要么是隱含在上下文之中。 We would have made a lot of money. 我們本來能夠掙很多錢的。 （2）用介詞代替條件狀語從句。常見的介詞有：with，without，but for等。 But for the rain (=If it had not been for the rain), we would have finished the work. 要不是下雨，我們就完成這項工作了。 Without electricity (=If there were no electricity), life would be quite different today. 如果沒有電，今天的生活就會是另一個樣子。 （3）用but，otherwise，or else等由真實語氣轉(zhuǎn)化為虛擬語氣或反之。 The captain kept calm in the terrible storm, otherwise the accident wouldn’t have been prevented. 船長在可怕的大風(fēng)暴中顯得很鎮(zhèn)靜，否則一場事故不可避免。 3. It is hard for me to imagine what I would be doing today if I ____________ in love, at the age of seven, with the Melinda Cox Library in my hometown. A. wouldn’t have fallen B. had not fallen C. should fall D. were to fall 【答案】B　 【名師點睛】錯綜條件句就是虛擬條件主句和從句的動作發(fā)生的時間不一致，因此，主句和從句的謂語動詞要根據(jù)各自所指的不同時間選擇適當(dāng)?shù)膭釉~形式。 If I were you, I would not have missed the film last night. 如果我是你，我不會錯過昨晚的電影。 If they had started in the early morning, they would arrive in half an hour. 如果他們清早就出發(fā)，那么再有半個小時就到了。 時態(tài)類型 主句謂語形式 條件句的謂語形式 例句 與現(xiàn)在事實相反 would / should / could / might + 動詞原形 動詞過去式did *be 多用were　 If I were you, I should study English. I would certainly go if I had time. 與過去事實相反 would / should / could / might + have done 動詞過去完成式 had done If you had taken my advice, you would not have failed in the test. If I had left a little earlier, I would have caught the train. 與將來事實相反 would / should / could / might + 動詞原形 動詞過去式 If you came tomorrow, we would have the meeting. If it were to rain tomorrow, the meeting would be put off. should + 動詞原形 were + to do　 注意： 1. would/should/could/might 主句謂語中的should主要用于第一人稱；would表示結(jié)果還表示過去經(jīng)常做某事，might表示可能性，could表示能力、允許或可能性。比較： If you tried again, you would succeed. 要是你再試一試，你就會成功的。 (would表結(jié)果) If you tried again, you might succeed. 要是你再試一試，你可能會成功的。 (might表可能) If you tried again, you could succeed. 要是你再試一試，你就能成功了。(could表能力) 2. 錯綜時間虛擬條件句 即條件從句與主句所指時間不一致，如從句指過去，而主句即指的是現(xiàn)在或?qū)?，此時應(yīng)根據(jù)具體的語境情況，結(jié)合上面提到的三種基本類型對時態(tài)作相應(yīng)的調(diào)整： If it had rained last night, the ground would be wet now. 要是昨晚下過雨的話，現(xiàn)在地面就會是濕的。 You would be much better now if you had taken my advice. 假若你當(dāng)時聽我的話，你現(xiàn)在就會好多了。 3. If虛擬條件句的否定（含蓄條件句） ?？純蓚€句型：If it weren’t for...和If it hadn’t been for...，其意為＂若不是(有)＂ ＂要不是＂。 If it weren’t for water, no plant could grow. 要是沒有水植物就無法生長。 If it hadn’t been for your assistance, we wouldn’t have succeeded. =But for your assistance, we wouldn’t have succeeded. =Without your assistance, we wouldn’t have succeeded. 要是沒有你的支持，我們不會成功的。 4. If虛擬條件句的倒裝形式，即把were，had，should置于句首。 Were I in school again (= If I were in school again), I would study harder. 如果我再上學(xué)，我一定更加努力地學(xué)習(xí)。 Had you asked me, I would have told you. =If you had asked me, I would have told you. 要是你問我的話，我就告訴你了。 易錯點4 忽視名詞性從句中虛擬語氣的用法 1. The doctor remended that you ______________ swim after eating a large meal. A. wouldn’t B. couldn’t C. needn’t D. shouldn’t 【錯因分析】考生容易誤選B項，原因是不知道remend的賓語從句中要用虛擬語氣。 【參考答案】D 2. It is important that we ______________. A. shall close the window before we leave B. will close the window be