1、專題五 情態(tài)動(dòng)詞和虛擬語(yǔ)氣,一、幾組情態(tài)動(dòng)詞的區(qū)別 1can 和 be able to can 與 be able to 都可以表示能力，但兩者在用法上有點(diǎn)差異：can(could) 表示主觀能力，不表示意愿；be able to 表示主觀意愿，強(qiáng)調(diào)要克服困難去做某事。它的將來(lái)時(shí)用will be able to。例如： My grandma is over seventy，but she can still read without glasses. He is able to give up his bad habits.,2must 和 have to must 和 have to 都可以

2、表示“必須”，但有幾點(diǎn)區(qū)別： (1)must 強(qiáng)調(diào)“內(nèi)在的職責(zé)”、“義務(wù)”，而 have to 強(qiáng)調(diào)“外界壓力”、“不得已而為之”。 (2)have to 可用于多種時(shí)態(tài)，而 must 一般用于現(xiàn)在時(shí)，其過(guò)去時(shí)與將來(lái)時(shí)分別由 had to 與 shall/will have to 代替。,(3)在回答 must 引起的問(wèn)題時(shí)，如果是否定的答復(fù)，不能用 mustnt，而要用 neednt 或 dont have to，因?yàn)?mustnt 是“一定不要”、“一定不能”、“禁止”的意思。例如： 1)You must come to the classroom before eight. 2)It i

3、s raining hard outside，but I have to leave now. 3)“Must we do it now？”“No，you neednt.”,3used todo，be used todoing 和 be used todo (1)used todo意為“過(guò)去常常做某事”，“過(guò)去一直做某事”；be used tov. ing/n.意為“習(xí)慣于”；be used todo 意為“被用來(lái)做某事”。 (2)used to 只表示過(guò)去，而 be used tov. ing/n.可表示現(xiàn)在、過(guò)去或?qū)?lái)。例如： 1)He used to smoke.Now he doesn

4、t. 2)Hes quite used to hard work/working hard. 3)The knife is used to cut bread.,4cant 與 mustnt cant 表示“不能”，是指無(wú)能力；mustnt 表示“不能”，指的是“禁止，不允許”。在口語(yǔ)里，cant 也可表示“禁止，不允許”，但語(yǔ)氣不如 mustnt 強(qiáng)。例如： He is so young that he cant go to school. Theres a meeting inside.You mustnt make any noise.,5can 和 may 考試中主要測(cè)試 can，ma

5、y 或 could，might，表示可能性的區(qū)別及對(duì) may 構(gòu)成的疑問(wèn)句的回答。 (1)can，could，may，might 都可以表示可能性。can，could 表示潛在的可能性或理論上或邏輯判斷上存在的可能性；而 may，might則表示事實(shí)上的可能性。此外，can，could 還有“有能力”的意思，而may與 might 不具有此意。例如： According to the weather forecast，it may rain tomorrow. Any man with a little sense can see that he is wrong.,(2)May I/we .

6、？這一類疑問(wèn)句的肯定回答為 Yes，please.或 Certainly；否定回答為 Please dont.或 No，you mustnt.例如： “May we leave now？”“No，you mustnt.You havent finished your homework yet.”,6情態(tài)動(dòng)詞動(dòng)詞完成式 情態(tài)動(dòng)詞動(dòng)詞完成式即“情態(tài)動(dòng)詞havedone”，表示對(duì)過(guò)去的行為或動(dòng)作進(jìn)行推測(cè)、評(píng)論或判斷。 (1)must have done must have done 表示對(duì)過(guò)去某事的肯定猜測(cè)。其否定或疑問(wèn)形式都用 can(could)來(lái)表示。例如： Since the road is

7、 wet，it must have rained last night. He cant have missed the way.I drew him a map. The dictionary has disappeared.Who could have taken it?,當(dāng)然對(duì)現(xiàn)在發(fā)生或?qū)?lái)發(fā)生的事情，要用 must do 表示猜測(cè)，否定式為 cant do。 He must understand that we mean business. You must be hungry after a long walk.,(2)may/might have done may/might ha

8、ve done 表示推測(cè)過(guò)去某事“也許”發(fā)生了，may 比 might 表示的可能性在說(shuō)話人看來(lái)稍大些。例如： I cant find my keys.I may/might have left them at the school yesterday. (3)could have done 在肯定句型中，往往表示委婉的批評(píng)。本可以做什么而沒(méi)做；有時(shí)也用作猜測(cè)。 You could have told us earlier. Tom could have taken the dictionary.,(4)ought to/should have done和ought not to/should

9、nt have done ought to/should have done和ought not to/shouldnt have done用于對(duì)已發(fā)生的情況表示“責(zé)備”、“不滿”，分別表示“本應(yīng)該”和“本不應(yīng)該”。例如： 1)With all the work finished，I should have gone to the party last night. 2)You ought not to have made fun of him.He is not the one you laugh at but learn from.,(5)neednt have done neednt h

10、ave done 表示過(guò)去做了某事，但沒(méi)有做的必要，意為“本沒(méi)必要”。例如： Yon neednt have waken me up; I dont have to go to work today. 注：表示推測(cè)過(guò)去某動(dòng)作發(fā)生的可能性時(shí)，就表示的可能性程度而言，must 最大，could 其次，may 更次之，might 最小。例如： I wonder how Tom knew about your past. He must/could/may/might have heard of it from Mary.,7情態(tài)動(dòng)詞動(dòng)詞進(jìn)行式 情態(tài)動(dòng)詞行為動(dòng)詞進(jìn)行式(即情態(tài)動(dòng)詞bedoing)，表示

11、推測(cè)或評(píng)論某動(dòng)作現(xiàn)在是否正在進(jìn)行。例如： (1)He must be playing basketball in the room. (2)She may be staying at home.,二、幾個(gè)情態(tài)動(dòng)詞使用的特定范圍 1表示推測(cè)時(shí)，can 不能用在肯定句中(但 could 可以)；may 和 might 不能用在疑問(wèn)句中。例如： Peter may come with us tonight，but he isnt very sure yet. Can it be a sunny day tomorrow?,2作為情態(tài)動(dòng)詞，need 和 dare 不能用在肯定句中(條件狀語(yǔ)從句除外)。

12、肯定句中，須把它們用作實(shí)義動(dòng)詞，后接帶 to 的不定式。例如： 【誤】We need hold a meeting to discuss the matter. 【正】We need to hold a meeting to discuss the matter. 【正】If you need hold a meeting to discuss the matter, Ill give you a help. 3在回答由 could 和 might 引起的表示請(qǐng)示的一般疑問(wèn)句時(shí)，不能用 could 和 might (應(yīng)分別用 can 和 may)回答。例如： Could I borrow yo

13、ur dictionary? Yes，of course you can.,三、一些“形義不一致”的現(xiàn)象 1過(guò)去式 could 或 might 后接動(dòng)詞原形可以表示對(duì)現(xiàn)在或?qū)?lái)(不是對(duì)過(guò)去)的推測(cè)。例如： Im afraid it might snow tonight. 2may (not) 和 cant 后接完成時(shí)態(tài)，表示對(duì)過(guò)去(不是對(duì)現(xiàn)在或?qū)?lái))的推測(cè)。例如： There were already five people in the car but they managed to take me as well. It cant have been a comfortable journ

14、ey.,四、情態(tài)動(dòng)詞的常用形式的特殊使用 1should 和 ought to 后接動(dòng)詞原形，常表示“應(yīng)該”；但也可用來(lái)表示推測(cè)，意為“想必會(huì)”。例如： (1)Its nearly seven oclock.Jack should be here at any moment. (2)When can I come for the photos? I need them tomorrow afternoon. They should be ready by 12：00. 2could 后接完成式常表示“(過(guò)去)可能”，但也可用來(lái)表示責(zé)備語(yǔ)氣，意為“過(guò)去本來(lái)能夠，而實(shí)際上卻未”。例如： We co

15、uld have walked to the station；it was so near. Yes.A taxi wasnt at all necessary.,五、虛擬語(yǔ)氣在條件句中的應(yīng)用 1虛擬條件句中謂語(yǔ)動(dòng)詞的形式,(1)主句中的 should，could，might 具有情態(tài)意義。 (2)與將來(lái)事實(shí)相反時(shí)，條件句中謂語(yǔ)可由“should動(dòng)詞原形”構(gòu)成，但要注意這里的 should 不能被 would，could，might 等替代。 (3)從句中單數(shù) be 動(dòng)詞的過(guò)去式一般用 were，在口語(yǔ)中有時(shí)也可用 was。 2有時(shí)候，從句與主句所指時(shí)間并不一致，這時(shí)謂語(yǔ)動(dòng)詞應(yīng)分別用其相應(yīng)的形

16、式。這時(shí)便稱為錯(cuò)綜時(shí)態(tài)虛擬條件句。例如： If he had studied hard, he would pass the exam tomorrow.,3條件句中的if省略時(shí)，從句應(yīng)倒裝。例如： Had they got enough boats，they would have succeeded in crossing the river. 但條件句的謂語(yǔ)是實(shí)義動(dòng)詞的過(guò)去式，即謂語(yǔ)部分沒(méi)有 had，were 或 should 時(shí)，if 不能省略，從句也不能倒裝。 4含蓄條件句 非真實(shí)條件有時(shí)不用條件句而用短語(yǔ)，或通過(guò)上下文含蓄地表達(dá)出來(lái)，但在意義上它們?nèi)韵喈?dāng)于條件句。例如： Withou

17、t your help，we couldnt have finished it on time. 要不是你幫忙，我們不可能按時(shí)完成它。,But for the storm，we would have arrived earlier. 要是沒(méi)有暴風(fēng)雨，我們還會(huì)到得早些。 The ship would have sunk had it not been for the captain.要不是船長(zhǎng)，船就沉了。 Im really busy.Otherwise I would go with you. 我很忙，不然我會(huì)和你去的。,六、虛擬語(yǔ)氣在其他情況下的應(yīng)用 1在賓語(yǔ)從句中的運(yùn)用 (1)sugges

18、t (建議)，ask，require，demand，decide，prefer，insist (堅(jiān)持要求)，command，order 等表示“建議”、“請(qǐng)求”、“主張”、“命令”之類的動(dòng)詞后接賓語(yǔ)從句時(shí)，從句須用虛擬語(yǔ)氣，其形式為“should動(dòng)詞原形”或“動(dòng)詞原形”。 但當(dāng) suggest 作“暗示”講，insist 作“堅(jiān)持說(shuō)、堅(jiān)持認(rèn)為”講時(shí)不用虛擬語(yǔ)氣。例如： All the doctors insisted that he was badly wounded and that he should be operated on at once. 所有的醫(yī)生都堅(jiān)持認(rèn)為他傷得很?chē)?yán)重，堅(jiān)決要

19、求他立刻手術(shù)。,特別提醒：除接賓語(yǔ)從句外，上述動(dòng)詞及其相應(yīng)的名詞后的主語(yǔ)從句、表語(yǔ)從句亦應(yīng)用虛擬語(yǔ)氣，形式同上。例如： It is requested that Mr Wang give a performance at the party.有人請(qǐng)求王先生在晚會(huì)上表演一個(gè)節(jié)目。(主語(yǔ)從句) My proposal is that we should give them more help. 我的建議是我們應(yīng)給予他們更多的幫助。(表語(yǔ)從句) He gave orders that the work be started at once. 他命令立即開(kāi)始工作。(同位語(yǔ)從句),特別提醒：idea，p

20、lan 等名詞后的表語(yǔ)從句或同位語(yǔ)從句也用虛擬語(yǔ)氣，形式同上。,(2)在 wish 后的賓語(yǔ)從句中，須用虛擬語(yǔ)氣，形式為：所述愿望與過(guò)去事實(shí)相反時(shí)用“had過(guò)去分詞”，與現(xiàn)在事實(shí)相反時(shí)用過(guò)去式，與將來(lái)事實(shí)相反時(shí)用“would(不用should)動(dòng)詞原形”。例如： I wish you had told me earlier. How I wish I were a bird! I wish someone would give me a hand. 特別提醒：wish 后接 that 從句時(shí)不能用來(lái)表示祝愿。,2在主語(yǔ)從句中的運(yùn)用 (1)在 It is necessary (important

21、，better，natural，strange，surprising) that 這一句型中，從句的謂語(yǔ)動(dòng)詞須用虛擬語(yǔ)氣，其形式為“should動(dòng)詞原形”或“動(dòng)詞原形”。例如： It is necessary that we should make our minds without delay. How surprising it is that he should have refused to come with you! 這一句型中的形容詞多是表示“重要性”、“必要性”和“合適性”的，有較強(qiáng)的建議、規(guī)勸和命令色彩。,(2)在It is a pity (a shame，no wonder

22、) that 這一句型中，從句的謂語(yǔ)動(dòng)詞須用虛擬語(yǔ)氣，其形式為“should動(dòng)詞原形”或“動(dòng)詞原形”。 3在狀語(yǔ)從句中的運(yùn)用 (1)as if/as though 從句若表示非真實(shí)情況可用虛擬語(yǔ)氣，其形式為：表示與過(guò)去事實(shí)相反時(shí)用“had過(guò)去分詞”，與現(xiàn)在事實(shí)相反時(shí)用“過(guò)去式”，與將來(lái)事實(shí)相反時(shí)用“would/were going to 等動(dòng)詞原形”。,特別提醒：as if還可以引導(dǎo)表語(yǔ)從句。例如： He looks as if he didnt agree to that plan. as if 可以跟在 look，seem，taste，smell 等連系動(dòng)詞后面引導(dǎo)一個(gè)表語(yǔ)從句，從句中的謂

23、語(yǔ)動(dòng)詞所表示的情況若可能是事實(shí)的，可用陳述語(yǔ)氣。例如： It looks as if it is going to rain. (2)in order that/so that 引導(dǎo)的目的狀語(yǔ)從句中的謂語(yǔ)動(dòng)詞一般要用虛擬語(yǔ)氣，其形式為：表示現(xiàn)在情況用“may/can動(dòng)詞原形”，表示過(guò)去用“might/could動(dòng)詞原形”。,(3)在 for fear that 和 in case 引導(dǎo)的狀語(yǔ)從句中也常用虛擬語(yǔ)氣，其形式為“should動(dòng)詞原形”。例如： She put a blanket over the baby for fear that he should catch a cold. I

24、n Britain，when people go out，they are used to taking umbrellas with them in case it should rain.,特別提醒：這一句型中的 should 也可視作情態(tài)動(dòng)詞，意為“萬(wàn)一”。 in case 引導(dǎo)的狀語(yǔ)從句中也可用陳述語(yǔ)氣。,4在其他情況下的運(yùn)用 (1)在It is(high)time that 這一結(jié)構(gòu)中，定語(yǔ)從句的謂語(yǔ)動(dòng)詞須用虛擬語(yǔ)氣，其形式為“過(guò)去式”或“should動(dòng)詞原形”。例如： It is time that we went to bed/we should go to bed. (2)當(dāng)

25、would rather，had rather 后接省去 that 的從句時(shí)，從句中的謂語(yǔ)須用虛擬語(yǔ)氣。其形式為：表示與過(guò)去事實(shí)相反時(shí)用“had過(guò)去分詞”；與現(xiàn)在或?qū)?lái)事實(shí)相反時(shí)用“過(guò)去式”。例如： I would rather he came tomorrow than today. 我寧愿他明天來(lái)，而不是今天。 這里的 would rather 和 had rather 在意義上相當(dāng)于 wish。,(3)在某些表示祝愿的句子中，也常用虛擬語(yǔ)氣，謂語(yǔ)動(dòng)詞一般由“原形動(dòng)詞”充當(dāng)。例如： “God bless you！”said the lawyer. Long live the Peoples

26、 Republic of China! 中華人民共和國(guó)萬(wàn)歲！ (4)在 if only 引起的句子中用虛擬語(yǔ)氣，其形式與 wish 引導(dǎo)的賓語(yǔ)從句中的形式相當(dāng)。例如： If only he had come in time. If only I had enough money, I could buy a car nicer than yours.,高考真題再現(xiàn) 1(2010全國(guó)卷)Just be patient. You _ expect the world to change so soon. Acant Bneednt Cmay not Dwill not 答案：A 解析：考查情態(tài)動(dòng)詞

27、辨析。句意為：耐心點(diǎn)兒。你不能指望世界立刻發(fā)生變化。cant表示“不能”；neednt意為“不必”；may not表示“不可能”；will not表示“不會(huì)”。只有A符合語(yǔ)意。,2(2010全國(guó)卷)Im afraid Mr. Harding _ see you now. Hes busy. Acant Bmustnt Cshouldnt Dneednt 答案：A 解析：考查情態(tài)動(dòng)詞。根據(jù)下一句中的內(nèi)容可知Mr. Harding現(xiàn)在“不能”見(jiàn)你。cant表示“不能”；mustnt表示“禁止”；shouldnt表示“不應(yīng)該”；neednt表示“不必”。,3(2010遼寧卷)Doctors say

28、that exercise is important for health, but it _ be regular exercise. Acan Bwill Cmust Dmay 答案：C 解析：考查情態(tài)動(dòng)詞辨析。句意為：醫(yī)生說(shuō)，鍛煉對(duì)于健康很重要，但是必須是經(jīng)常的鍛煉。情態(tài)動(dòng)詞must表示”必須”，符合語(yǔ)意。,4(2010安徽卷)Jack described his father, who _ a brave boy many years ago, as a strongwilled man. Awould be Bwould have been Cmust be Dmust have b

29、een 答案：D 解析：杰克把他的父親描述成一個(gè)意志堅(jiān)強(qiáng)的人，此處表示的是對(duì)過(guò)去事實(shí)的推測(cè)，所以用must have done結(jié)構(gòu)。注意句中有一個(gè)非限制性定語(yǔ)從句將主句分隔開(kāi)了。,5(2010天津卷)John went to the hospital alone. If he _ me about it, I would have gone with him. Ashould tell Btells Ctold Dhad told 答案：D 解析：考查虛擬語(yǔ)氣。由此處的主句可知，這里表示與過(guò)去事實(shí)相反的假設(shè)，故條件句中應(yīng)用過(guò)去完成時(shí)。,6(2010福建卷)Teachers recommend

30、parents _ their children under 12 to ride bicycles to school for safety. Anot allow Bdo not allow Cmustnt allow Dcouldnt allow 答案：A 解析：考查虛擬語(yǔ)氣。句意為：老師建議家長(zhǎng)為了安全起見(jiàn)，不要讓12歲以下的孩子騎自行車(chē)上學(xué)。recommend后的賓語(yǔ)從句中的謂語(yǔ)形式應(yīng)為should do結(jié)構(gòu)，should可以省略。故答案為A項(xiàng)。,7(2010重慶卷)You _ park here! Its an emergency exit. Awouldnt Bneednt Cc

31、ouldnt Dmustnt 答案：D 解析：考查情態(tài)動(dòng)詞。根據(jù)題干中的emergency exit可知“此處是不允許停車(chē)的”，故用mustnt表示禁止。,8(2010四川卷)_ I take the book out? Im afraid not. AWill BMay CMust DNeed 答案：B 解析：考查情態(tài)動(dòng)詞。 may表示征求對(duì)方的許可。,9(2010浙江卷)Had I known about this computer program, a huge amount of time and energy _. Awould have been saved Bhad been s

32、aved Cwill be saved Dwas saved 答案：A 解析：考查虛擬語(yǔ)氣。從前面Had I known about .知，此處是if條件句對(duì)過(guò)去情況的虛擬，所以主句用should/would/could/mighthave done結(jié)構(gòu)，故排除B、C和D三項(xiàng)，選A項(xiàng)。,10(2010江蘇卷)George is going to talk about the geography of his country, but Id rather he _ more on its culture. Afocus Bfocused Cwould focus Dhad focused 答案：

33、B 解析：考查虛擬語(yǔ)氣。would rather后的賓語(yǔ)從句的謂語(yǔ)動(dòng)詞用一般過(guò)去式，表示對(duì)現(xiàn)在或?qū)?lái)事實(shí)的虛擬。,名校模擬演練 1(2010山東濰坊質(zhì)量監(jiān)測(cè))The order came that the medical supplies _ to Beijing for the H1N1 flu soon. Awould be sent Bshould send Cbe sent Dmust be sent 答案：C 解析：考查虛擬語(yǔ)氣。當(dāng)表示愿望、請(qǐng)求、建議、命令等意義的動(dòng)詞(如order, suggest, command等)后面接從句時(shí)，從句用虛擬語(yǔ)氣，從句謂語(yǔ)用shoulddo, s

34、hould可以省略。故選C。,2(2010安徽皖南八校二聯(lián))When shall we meet your cousin at the station? His plane took off 2 hours ago, and it _ arrive at 5 pm. Ashould Bcould Cmust Dcan 答案：A 解析：考查情態(tài)動(dòng)詞的用法。should的意思是“應(yīng)該會(huì)，可能”，在這里表示對(duì)將來(lái)的推測(cè)，預(yù)期會(huì),3(2010長(zhǎng)春調(diào)研)Has Tim started? He said he would join in the party. He _. He is a man of hi

35、s word. Acould have left Bmust have left Ccant come Dwont be coming 答案：B 解析：考查情態(tài)動(dòng)詞。根據(jù)“He is a man of his word”可知他是一個(gè)守信的人，因此推測(cè)他肯定已經(jīng)啟程了。,4(2010北京東城期末)The traffic is heavy now, so Mike _ come late. Lets wait ten more minutes. Acan Bneed Cmay Dshall 答案：C 解析：考查情態(tài)動(dòng)詞的用法。句意為：現(xiàn)在交通繁忙，所以Mike可能會(huì)遲到。那讓我們?cè)俚?0分鐘吧。此處may表示“(有可能但不肯定)也許，可能”；can表示“能夠”；need表示“需要”；shall用于第二、三人稱的陳述句中，表示“警告、命令、威脅”等語(yǔ)氣。據(jù)此選C項(xiàng)。,5(2010北京海淀期末)If you _ to my birthday party last Saturday, you would have met our old friend Jim. Oh, what a pity! Acame Bhad come Cwould come Dwould have come 答案：B 解析：考查虛擬