【正文】 用于疑問句、否定句和條件從句中，一般不用在肯定句中。如： I dare to swim across this river. He does not dare (to) answer. Don39。如： You shall fail if you don39。 ② You are mistaken, I should say. 依我看，你是搞錯(cuò)了。 Should還可以用在if引導(dǎo)的條件從句，表示一件事聽起來可能性很小，但也不是完全沒有可能。 ⑥ If you should change your mind, please let us know. 萬一你改變主意，請(qǐng)通知我們。如： ⑧ Why should you be so late today? 你幾天怎么來得這么晚？ ⑨ — Where is Betty living? — 貝蒂住在哪里？ — How should I know? — 我怎么會(huì)知道呢？ ⑩ I don39。如： Would you pass me the book? 2. 表示意志、愿望和決心。如： This will be the book you want. He will have arrived by now. The guests would have arrived by that time. I thought you would have finished this by now. 4. Would可表示過去反復(fù)發(fā)生的動(dòng)作或某種傾向。如： You ought to take care of him. 2. 表示推測(cè)。 注意：在美國英語中，ought to用于否定句和疑問句時(shí)，to可以省略。 ，而should卻相當(dāng)常用。t to go there. I didn39。ju:snt]。t she? （口語+常用）/ use(d)n39。t we better stop now? (Had we better not stop now?) I think I39。如： I39。如： I would rather work on a farm than in a factory. I would rather watch TV than go to see the film. I would rather lose a dozen cherry trees than that you should tell me one lie. I39。 Can you pass me the books? 你能給我遞一下書嗎 ? Could you help me, please? 請(qǐng)問,你能幫助我嗎? What can you do? 你能干點(diǎn)什么呢? Can you be sure? 你有把握嗎? can 和could 只能用于現(xiàn)在式和過去式兩種時(shí)態(tài),將來時(shí)態(tài)用 be able to 來表示。 may (might) 可以, 表示說話人同意,許可或請(qǐng)求對(duì)方許可。 He told me he might be here on time. 他說他能按時(shí)間來。 I must finish my work today. 我今天必須完成我的工作。 He must be the man I am looking for. 他一定是我要找的人。 He must have told my parents about it. 他一定把這件事情告訴我父母親了。clock already, we must have been late again. 已經(jīng)六點(diǎn)鐘了，我們一定又遲到了。(客觀條件必須現(xiàn)在走) need 需要 多用在否定式或疑問句中. Need I attend the meeting tomorrow? 我需要明天參加會(huì)議嗎? You need not hand in the paper this week. 這一周你不必交論文。 needn39。 dare 敢 多用在否定或疑問句中。t dare to tell the teacher what happened that day. 他不敢告訴老師那天發(fā)生的事。 ought + to have done 句型。表示一件不該做的事情卻做了。 I39。s the last time. 我再不會(huì)做那件事情了,這是最后一次。s hot. Will you open the windows? 天氣太熱了,你能打開窗戶嗎? Will you help me to work it out? 你能幫我解這道題嗎? Would you like some coffee？ 給你來點(diǎn)咖啡怎樣？ Shall, should表示命令,警告,允諾,征求,勸告,建議驚奇。 I have to go now. 我現(xiàn)在得走了。 。 You must be here on time next time. 你下次一定要按時(shí)來。 This should be no problem. 這應(yīng)該沒問題。 will, would用于疑問句表示說話人向?qū)Ψ教岢稣?qǐng)求或詢問,用 would 比 will 更婉轉(zhuǎn),客氣。 I39。 will (would)決心,愿望。 You ought to have been here yesterday. 你昨天就應(yīng)該來。 You ought to read these books if you want to know how to repair the motorcar. 如果你想知道如何修理汽車,你應(yīng)該讀這些書。 Dare you catch the little cat? 你敢抓小貓嗎? dare 除用作情態(tài)動(dòng)詞外,更多的是當(dāng)實(shí)義動(dòng)詞使用, 用法同實(shí)義動(dòng)詞一樣,要考慮人稱,單復(fù)數(shù),時(shí)態(tài)等。 You needn39。 I need a bike to go to school. 我上學(xué)需要一輛自行車。 You must do it now. 你必需現(xiàn)在就干。 It39。s calling him that day. 那天他要走是因?yàn)橛腥私兴?。t work all the time. 你不能老是工作。 must, need, ought to, dare (dared)用法Must 必須,應(yīng)該,一定,準(zhǔn)是, 表示說話人認(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)。 may 否定式為 may not, 縮寫形式是 mayn39。 With the teacher39。t talk about this to anyone. （句中的39。t you rather stay here? — No, I would not. I39。②You had better … 用于同輩或小輩，對(duì)長輩不可用。如： — We had better go now. — Yes, we had (we39。t you to be interested in the theatre? Didn39。t 亦可拼作usen39。 used to，had better，would rather的用法1. Used to表示過去的習(xí)慣動(dòng)作或狀態(tài)，現(xiàn)在已不存在，在間接引語中，其形式可不變。t smoke so much. ought和should的區(qū)別： 。如： You ought to have asked him (but you didn39。如： The wound would not heal. During the vacation he would visit me every week. 5. 表料想或猜想。t open 3. 用“will be”和“will(would) + have + 過去分詞”的結(jié)構(gòu)表示推測(cè)，主要用于第二、三人稱。 2. “should + have + 過去分詞”結(jié)構(gòu)一般表示義務(wù)，表示應(yīng)該做到而實(shí)際上沒有做到，并包含一種埋怨、責(zé)備的口氣。 此外，Why(or How) + should結(jié)構(gòu)表示說話人對(duì)某事不能理解，感到意外、驚異等意思。從句謂語由should加動(dòng)詞原形構(gòu)成，主句謂語卻不一定用虛擬語氣。 ④ This is something I should have liked to ask you. 這是我本來想問你的。如： You should go to class right away. Should I open the window? Should的含義較多，用法較活，現(xiàn)介紹三種其特殊用法。如： What shall we do this evening? 2. Shall用于第一、第三人稱疑問句中，表示說話人征求對(duì)方的意見或向?qū)Ψ秸?qǐng)示。m unfair. He daren39。t + 不定式的完成式“表示本來不必做某事而實(shí)際上做了某事”。 ④ 詢問對(duì)方的意愿時(shí)應(yīng)用must。如： You mustn39。 He must have been to Shanghai. 4. have to的含義與must相似，兩者往往可以互換使用，但have to有各種形式，隨have的變化而定。t have to。如： He may not have finished the work. must和have to的用法1. 表示必須、必要。在日常口語中，用Can I ... 征詢對(duì)方意見在現(xiàn)代口語中更為常見。 表示請(qǐng)求、允許時(shí)，might比may的語氣更委婉一些，否定回答時(shí)(口語中常用) no , you can39。如： I39。t you? 3） 構(gòu)成修辭倒裝： Nowhere can he obtain any information about his sister. Hardly had he arrived when she started plaining. 4） 代替限定動(dòng)詞詞組： A: Who can solve this crossword puzzle? B: Tom can. A: Shall I write to him? B: Yes, do. can和could的用法1. 表示能力或客觀可能性，還可以表示請(qǐng)求和允許。 shall, should。 情態(tài)動(dòng)詞數(shù)量不多,但用途廣泛,主要有下列: can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to) ,had better. 功能助動(dòng)詞(auxiliary)主要有兩類：基本助動(dòng)詞(primary auxiliary)和情態(tài)助動(dòng)詞(modal auxiliary)。 用法是：情態(tài)動(dòng)詞+行為動(dòng)詞原形 例