【正文】 able to explain what had ，他還是將事情的經(jīng)過(guò)解釋清楚了（而不是“他有能力解釋清楚”）。She can sing that song in 。He could hardly support his family before he found the new 法養(yǎng)家。2)表示可能（理論上或邏輯判斷上）表示客觀上的可能性The temperature can fall to60c, You mustn’t smoke while you’re walking around in the can start a can borrow this useful book from the 。Now people can skate on the 。3)表示主觀上的允許Can I ask you some questions about it ?我可以問(wèn)你有關(guān)這件事的幾個(gè)問(wèn)題嗎？You can not leave here till I e 。t happen any more 。t / can39。He couldn39。t be over 。這時(shí)候，could就不可以看作是can的過(guò)去式了。如：Could you speak a little slowly ?您能稍微說(shuō)慢一點(diǎn)兒?jiǎn)?？I39。t give you any definite answer at this 。We would appreciate it if you could offer us any ，我們將不甚感激。（二）情態(tài)動(dòng)詞情態(tài)動(dòng)詞表示說(shuō)話人對(duì)某一動(dòng)作或狀態(tài)的態(tài)度，可以表示“可能”、“可以”、“需要”、“必須”或“應(yīng)當(dāng)”等之意。但不能單獨(dú)作謂語(yǔ)動(dòng)詞用，必須和不帶to的不定式連用構(gòu)成謂語(yǔ)動(dòng)詞。將情態(tài)動(dòng)詞置于主語(yǔ)之前即構(gòu)成其疑問(wèn)式，在情態(tài)動(dòng)詞之后加not既構(gòu)成其否定式。s?(3)表示“許可”時(shí)can可以和may換用，如：You can(may)go home now.(4)如果要表示語(yǔ)氣婉轉(zhuǎn)，可用could代替can，這時(shí)could不再是can的過(guò)去式，如：Could you e again tomorrow?(5)can和be able to都可表示能力，兩者在意思上沒(méi)有什么區(qū)別。如：He was able to go to the party yesterday evening in spite of the heavy 、may和might(might為may的過(guò)去式)的基本用法may , might 或許，可能，可以（might可以看作是may的過(guò)去式，這兩個(gè)詞除了時(shí)態(tài)不相同外，在表達(dá)意思的許多方面是相近的。）成語(yǔ)： may/might as well，后面接不帶to 的不定式，意為“不妨”。如： May you have a good 。而用比較婉轉(zhuǎn)的說(shuō)法進(jìn)行回答。t，表示“不應(yīng)該”，“不準(zhǔn)”、“不許可”或“禁止”之意，如：We must study hard and make progress every mustn39。t或用don39。t)have to(不必)來(lái)回答，而不用mustn39。t表示的是“禁止”或“不許可”之意，如：Must we finish the work tomorrow?No, you needn39。t have to), but you must finish it in three days.(3)在肯定句中must可以表示推測(cè)，表示“一定”或“必定”之意，如：Whose new bike can it be?It must be Liu Dong39。如：When did you answer her letter?Only 39。如果使用might，語(yǔ)氣就比較婉轉(zhuǎn)或更加不肯定，如：Mary might have learned some Chinese before.②可以表示過(guò)去本來(lái)可以做到而實(shí)際沒(méi)有做到的事情，有“勸告”或“責(zé)備”的語(yǔ)氣，如：You didn39。t 而需要用needn39。t have to，因?yàn)閙ustn39。例如：Must we hand in our exercises today ? 我們今天必須交作業(yè)嗎？Yes , you ，必須交。t(or , you don39。ought to的基本用法(l)表示根據(jù)某種義務(wù)或必要“應(yīng)當(dāng)”做某事，語(yǔ)氣比should強(qiáng)，例如：Everyone ought to obey the traffic regulations.(2)表示推測(cè)，注意與must表示推測(cè)時(shí)的區(qū)別：He must be home by now.(斷定他已到家)，He ought to be home by now.(不十分肯定)，This is where the oil must be.(比較直率)，This is where the oil ought to be.(比較含蓄)；(3)“ought + have+ 過(guò)去分詞”表示過(guò)去應(yīng)做某事而實(shí)際未做。注意，在美國(guó)英語(yǔ)中ought to 用于否定和疑問(wèn)句時(shí)to可以省略。t worry about us now.(2)need也可作為行為動(dòng)詞用，可用于肯定句，否定句和疑問(wèn)句中，其后可接名詞、代詞、動(dòng)名詞或帶 to 的動(dòng)詞不定式為其賓語(yǔ)。t后接完成式可以表示過(guò)去做了一件本來(lái)不必要做的事情shall的基本用法(1)shall用作情態(tài)動(dòng)詞時(shí)，用于第二、三人稱(chēng)，表示說(shuō)活人的意愿，可表示“命令”、“警告”、“強(qiáng)制”、“威脅”或“允諾”等意，如：He shall go first, whether he wants to or not.(2)在疑問(wèn)句中，shall用于第一、三人稱(chēng)，表示說(shuō)話人的征詢(xún)對(duì)方意見(jiàn)或請(qǐng)求指示，Shall用于第一人稱(chēng)和第三人稱(chēng)的疑問(wèn)句中是向聽(tīng)話人征求意見(jiàn)或命令。Example dialogues: ① Martin: Shall I bring my pen to the meeting tomorrow, sir? = Do you want me to… 我要不要明天把筆帶來(lái)開(kāi)會(huì)，老師？Teacher: Yes, you you shall tell other students to do the same and that they shan’t be late.= I demand that you tell… and that they shouldn’t be 。should的基本用法用于表示“建議、命令、要求、主張、指示”類(lèi)含義的名詞性從句中的謂語(yǔ)部分should do,但should可以省略；6)用在虛擬語(yǔ)氣句子中，表示發(fā)生的可能性不大，但也并非全無(wú)可能性，可譯為“萬(wàn)一”，如：If it should rain, buy an umbrella.= Should it rain, buy… 萬(wàn)一下雨就買(mǎi)一把傘。7）還可以表示興奮或吃驚，可譯為“竟然”，如: Guess who that man should be my favorite 。It’s amazing that she should be the only student who has won the ，真是神了。Should 表推測(cè)，想必一定，照說(shuō)應(yīng)該、估計(jì)。Used to 表示過(guò)去的習(xí)慣動(dòng)作或狀態(tài)，現(xiàn)在不復(fù)發(fā)生或存在，疑問(wèn)式和否定式有兩種。主要表示下面幾層意思： 1）許諾You shall hear everything directly you 。” I don39。she shan39。I promise that you shall see her again before 。She shall not stay in my 。You shall do as you are 。It has been decided that he shall be given the 。4）規(guī)定Each petitor shall wear a 。The supplier shall make shipment before October and the purchaser shall make payment within 15 days after receipt of the ，買(mǎi)方在收到貨物后十五天內(nèi)付款。主要用于下面幾個(gè)方面。t e to such a decision 。We should read English aloud every 。2）表示對(duì)某種情況的估計(jì)She shouldn39。The effect of the tax should be felt in higher 。This book should be published in two months at 。Why should I pay him for nothing ? 我干嗎要無(wú)為地付給他錢(qián)？ It seems so unfair that this should happen to 。s strange that it should be so cold ，今天怎么會(huì)這么冷。If it had not been for the doctor39。She stood away so that he should enter the room ，好讓他第一個(gè)進(jìn)入房間。ll write it down lest I should forget it 我將它記下以免遺忘。用于表示一種驚訝的語(yǔ)氣，should的這一用法也是考試中常常出現(xiàn)的考點(diǎn)之一：例：It is unthinkable that a strong character like Nancy should find a weakwilled man acceptable.（象南希這樣很有主見(jiàn)的女子竟然覺(jué)得一個(gè)意志軟弱的男子也可以接受，真讓人不可想象。）will , would（would可以看作是will的過(guò)去式，這兩個(gè)詞除了時(shí)態(tài)不相同外，在表達(dá)意思的許多方面是相近的。）1）用于第二人稱(chēng)疑問(wèn)句，表示請(qǐng)求（在這種用法中would使語(yǔ)氣更為客氣、委婉）Will you tell her that I39。t you e in and have a little whisky ? 你要不要進(jìn)來(lái)喝一點(diǎn)兒威士忌？（或是：你進(jìn)來(lái)喝一點(diǎn)兒威士忌，好嗎？）Would you tell me how to get to the shopping center ? 您能告訴我怎么去購(gòu)物中心嗎？ 2）用于表示愿望Go where you 。He wouldn39。They had to obey whether they would or 。Oil and water will not 。4）表示猜測(cè)（可譯成“一定是……、想必……，等”）This will be the house you39。He will have gone back to New 。5）will用于表示決心（可譯成“一定要,決心，等”）We will never talk about that subject 。6）would常用于虛擬條件句，表示與事實(shí)相反或不太可能實(shí)現(xiàn)的情況But for your help we would have been 。t worry about won39。表示猜測(cè)、推測(cè)must常用于肯定句中表示猜測(cè)。例如：You must be tired after working so ，肯定累了吧。The idea must be accepted by the society sooner or 。I didn39。情態(tài)動(dòng)詞詳解關(guān)鍵字： 師生交流 作者：林建華 更新時(shí)間：20081220 08:42:00一、情態(tài)動(dòng)詞的定義情態(tài)動(dòng)詞是一種本身有一定的詞義，表示說(shuō)話人的情緒、態(tài)度或語(yǔ)氣的動(dòng)詞，但不能單獨(dú)作謂語(yǔ)，只能和其他動(dòng)詞原形構(gòu)成謂語(yǔ)。May I have your name? 我能知道你的名字嗎？Shall we begin now? 我們現(xiàn)在就開(kāi)始嗎？You must obey the school 。I can see ，過(guò)來(lái)吧。What can I do for you? 你要什么？How dare you treat us like that!你怎么敢那樣對(duì)待我們?nèi)⑶閼B(tài)動(dòng)詞的特點(diǎn)情態(tài)動(dòng)詞無(wú)人稱(chēng)和數(shù)的變化，情態(tài)動(dòng)詞后面跟的動(dòng)詞需用原形，否定式構(gòu)成是在情態(tài)動(dòng)詞后面加“not”。He could be here 。t carry the heavy 。m sorry I can39。四、情態(tài)動(dòng)詞的用法(could)表示說(shuō)話人能, 可以, 同意, 準(zhǔn)許, 以及客觀條件許可, could 為can 的過(guò)去式。He could help us at 。(might)“可以”，表示說(shuō)話人同意，許可或請(qǐng)求對(duì)方許可。May I e in? 我可以進(jìn)來(lái)嗎?May I use your dictionary? 我可以用你的詞典嗎? You may put on more 。may 否定式為 may not, 縮寫(xiě)形式是 mayn?t。He told me he might be here on 。 “必須；應(yīng)該；一定；準(zhǔn)是”，表示說(shuō)話人認(rèn)為有必要做某事，命令、要求別人做某事以及對(duì)事物的推測(cè)。I must finish my work 。t work all the 。He must be the man I am looking 。值得注意的是：（1）must + have + 過(guò)去分詞，表示現(xiàn)在對(duì)過(guò)去事物的推測(cè)。He must have received my letter 。s six o39。（2）must 和 have to 的區(qū)別: must 表示說(shuō)話人的主觀思想, have to “不得不,必須”，表示客觀需要、客觀條件只能如此。(說(shuō)話人認(rèn)為必須現(xiàn)在干)I have to go 。I have to cook for