參見(jiàn)：必修三UNIT1、2情態(tài)動(dòng)詞中還做助動(dòng)詞有：will，would ，shall，should實(shí)義動(dòng)詞：need，dare 一、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)。 We can be there on time tomorrow. 我們明天能按時(shí)去那兒。 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 rules. 你必須遵守校規(guī)。 二、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) .,has to /have/had to, had better情態(tài)動(dòng)詞的位置: 情態(tài)動(dòng)詞在句中放在謂語(yǔ)動(dòng)詞之前, 謂語(yǔ)動(dòng)詞前若有助動(dòng)詞,則在助動(dòng)詞之前,疑問(wèn)句中, 情態(tài)動(dòng)詞則在主語(yǔ)之前。 I can see you. Come here. 我能看見(jiàn)你，過(guò)來(lái)吧。 He must have been away. 他一定走了。 What can I do for you? 你要什么？ How dare you treat us like that！ 你怎能那樣對(duì)待我們！ 三、情態(tài)動(dòng)詞的特點(diǎn): 一般情況下，情態(tài)動(dòng)詞無(wú)人稱和數(shù)的變化, (has to,have to;shall第一人稱 )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。 個(gè)別情態(tài)動(dòng)詞有現(xiàn)在式和過(guò)去式兩種形式, 過(guò)去式用來(lái)表達(dá)更加客氣, 委婉的語(yǔ)氣, 時(shí)態(tài)性不強(qiáng), 可用于過(guò)去，現(xiàn)在或?qū)?lái)。 He could be here soon. 他很快就來(lái)。 We cant carry the heavy box. 我們搬不動(dòng)那箱子。 Im sorry I cant help you. 對(duì)不起，我?guī)筒簧夏恪?四、情態(tài)動(dòng)詞的用法: can (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。 Can you pass me the books? 你能給我遞一下書嗎 ? Could you help me, please? 請(qǐng)問(wèn),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(guò)去式兩種時(shí)態(tài),將來(lái)時(shí)態(tài)用 be able to 來(lái)表示。 He could help us at all. 他完全可以幫助我們。 With the teachers help,I shall be able to speak English correctly. 由于老師的幫助,我將能準(zhǔn)確地講英語(yǔ)。 may (might) 可以, 表示說(shuō)話人同意,許可或請(qǐng)求對(duì)方許可。 You may take the book home. 你可以把書帶回家去. May I come 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 clothes. 你可以多穿點(diǎn)衣服. He said he might lend us some money. 他說(shuō)他可以借給我們一些錢。 may 否定式為 may not, 縮寫形式是 maynt. might 是may 的過(guò)去式, 有兩種用法, 一種表示過(guò)去式，一種表示虛擬語(yǔ)氣, 使語(yǔ)氣更加委婉, 客氣或?qū)赡苄缘膽岩伞?He told me he might be here on time. 他說(shuō)他能按時(shí)間來(lái)。 Might I borrow some money now. 我可以借點(diǎn)錢嗎? He might be alive. 他可能還活著。 Must 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)。 must 用來(lái)指一般現(xiàn)在時(shí)和一般將來(lái)時(shí), 過(guò)去式可用 have to 的過(guò)去式代替。 I must finish my work today. 我今天必須完成我的工作。 You mustnt work all the time. 你不能老是工作。 Must I return the book tomorrow? 我必須明天還書嗎? After such a long walk, you must be tired. 走了這么長(zhǎng)的路,你一定困了。 He must be the man I am looking for. 他一定是我要找的人。 He had to go because of somebodys calling him that day. 那天他要走是因?yàn)橛腥私兴?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 told my parents about it. 他一定把這件事情告訴我父母親了。 He must have received my letter now. 他現(xiàn)在一定收到我的信了。 Its six oclock already, we must have been late again. 已經(jīng)六點(diǎn)鐘了，我們一定又遲到了。 must 和 have to 的區(qū)別: must 表示說(shuō)話人的主觀思想, have to 表示客觀需要。 You must do it now. 你必需現(xiàn)在就干。(說(shuō)話人認(rèn)為必須現(xiàn)在干) I have to go now. 我得走了。(客觀條件必須現(xiàn)在走) need 需要 多用在否定式或疑問(wèn)句中. 單獨(dú)用為實(shí)義動(dòng)詞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。 need 是一個(gè)情態(tài)動(dòng)詞, 他的用法完全和其他情態(tài)動(dòng)詞一樣, 但 need 還可當(dāng)作實(shí)義動(dòng)詞使用, 這時(shí) need 就象其他動(dòng)詞一樣,有第三人稱,單復(fù)數(shù), 后面加帶 to 的動(dòng)詞等特性。 I need a bike to go to school. 我上學(xué)需要一輛自行車。 Do you need a dictionary? 你需要詞典嗎? She needs a necklace. 她需要一條項(xiàng)鏈。 neednt + have + 過(guò)去分詞 表示過(guò)去做了沒(méi)必要做的事情。 You neednt have taken it seriously. 這件事情你不必太認(rèn)真。 dare 敢 多用在否定或疑問(wèn)句中。 The little girl dare not speak in public. 小女孩不敢在公眾面前說(shuō)話。 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。 Do you dare to walk in the dark? 你敢黑夜走路嗎？ He doesnt dare to tell the teacher what happened that day. 他不敢告訴老師那天發(fā)生的事。 ought 應(yīng)當(dāng),應(yīng)該 后面跟帶有 to 的動(dòng)詞不定式。 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。 You ought to bring the child here. 你應(yīng)該把孩子帶來(lái)。 ought + to have done 句型。指過(guò)去動(dòng)作,表示一件事情該做而未做。 You ought to have been here yesterday. 你昨天就應(yīng)該來(lái)。 ought not to have done 句型。表示一件不該做的事情卻做了。 You ought not to have taken the book out of the reading-room. 你不應(yīng)該把書帶出閱覽室。 will (would)決心,愿望。 would 為 will 的過(guò)去式, 可用于各人稱。 Ill do my best to catch up with them. 我要盡全力趕上他們。 Ill never do it again, thats the last time. 我再不會(huì)做那件事情了,這是最后一次。 He said he would help me. 他說(shuō)他會(huì)幫助我。 will, would用于疑問(wèn)句表示說(shuō)話人向?qū)Ψ教岢稣?qǐng)求或詢問(wèn),用 would 比 will 更婉轉(zhuǎn),客氣。 Its hot. Will you open the windows? 天氣太熱了,你能打開(kāi)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(lái)點(diǎn)咖啡怎樣？ Shall, should表示命令,警告,允諾,征求,勸告,建議驚奇。 You should hand in the exercise book. 你應(yīng)該交作業(yè)本兒了。 This should be no problem. 這應(yīng)該沒(méi)問(wèn)題。 Shall we go now. 我們現(xiàn)在可以走了嗎? Why should I meet him？ 為什么我要見(jiàn)他? have to,不得不,必須,表示客觀條件只能如此, 而must 則表示主觀思想必須。 I have to go now. 我現(xiàn)在得走了。 I have to cook for my child. 我得給孩子做飯。 You must be here on time next time. 你下次一定要按時(shí)來(lái)。 We must go to get the timetable ourselves. 我們一定要自己去拿時(shí)刻表。情態(tài)動(dòng)詞 (Model Verbs) 又稱為情態(tài)助動(dòng)詞 (Model Auxil-iaries), 主要有can, may, must, could, might, shall , should, will, would, ought to, need, dare等。情態(tài)動(dòng)詞與其他動(dòng)詞連用表示說(shuō)話人的語(yǔ)氣。情態(tài)動(dòng)詞可表達(dá)建議、要求、可能和意愿等。情態(tài)動(dòng)詞沒(méi)有人稱和數(shù)的變化。在大學(xué)英語(yǔ)考試中，情態(tài)動(dòng)詞部分重點(diǎn)測(cè)試以下內(nèi)容： （1）情態(tài)動(dòng)詞+動(dòng)詞完成式: must have done （2）情態(tài)動(dòng)詞+動(dòng)詞進(jìn)行式: must be doing （3）情態(tài)動(dòng)詞+動(dòng)詞完成進(jìn)行式: must have been doing （4）某些情態(tài)動(dòng)詞的特殊用法: need 一、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+ have + done分詞”，表示對(duì)過(guò)去行為或動(dòng)作進(jìn)行推測(cè)、評(píng)論或判斷。 1. must have donemust 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 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 have 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, 往往用作委婉的批評(píng). 本應(yīng)該做什么,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 / shouldnt 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 have 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： You 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.” 二、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+ be + doing形式），表示推測(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. 三、情態(tài)動(dòng)詞+動(dòng)詞完成進(jìn)行式 情態(tài)動(dòng)詞+行為動(dòng)詞完成進(jìn)行式（即情態(tài)動(dòng)詞+ have been + v-ing 形式），表示推測(cè)或評(píng)論過(guò)去某動(dòng)作是否正在進(jìn)行或一直在進(jìn)行。例如： 1）They should have been meeting to discuss the problem. 2）He may / might have been buying stamps in the post office when you saw him. 四、某些情態(tài)動(dòng)詞的特殊用法 1. need 考試中主要測(cè)試 need 作情態(tài)動(dòng)詞與作實(shí)義動(dòng)詞的區(qū)別.情態(tài)動(dòng)詞need與實(shí)義動(dòng)詞need 在時(shí)態(tài)、肯定、否定結(jié)構(gòu)上的對(duì)比見(jiàn)下表。時(shí)態(tài) 情態(tài)動(dòng)詞need 實(shí)義動(dòng)詞 need 現(xiàn)在時(shí) He need (neednt) doNeed he do.? He needs (doesnt need) to do 過(guò)去時(shí) He needed (didnt need) to do 將來(lái)時(shí) He need (neednt) doNeed he do.? He will (not) need to do 注: need 一般用于否定句或疑問(wèn)句. 2. dare 考試中主要測(cè)試dare作情態(tài)動(dòng)詞和作實(shí)義動(dòng)詞的區(qū)別。情態(tài)動(dòng)詞dare 與實(shí)義動(dòng)詞dare 在時(shí)態(tài)、肯定、否定、疑問(wèn)結(jié)構(gòu)上的對(duì)比見(jiàn)下表。句型 情態(tài)動(dòng)詞dare 實(shí)義動(dòng)詞 dare 肯定句 現(xiàn)在時(shí) dare to 少用過(guò)去時(shí) dare to 少用 現(xiàn)在時(shí) dare/dares to do過(guò)去時(shí) dared to do 否定句 現(xiàn)在時(shí) darent/dare not do過(guò)去時(shí) dared not do 現(xiàn)在時(shí) do/does not dare (to) do過(guò)去時(shí) did not dare (to) do 疑問(wèn)句 現(xiàn)在時(shí) Dare he do? 過(guò)去時(shí) Dared he do? 現(xiàn)在時(shí) Do you/Does he dear (to) do? 過(guò)去時(shí) Did he dare (to) do 3. can 和 may考試中主要測(cè)試can，may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還具有“有能力”的意思，而may與might則不具此意。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 ？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 home work yet.” 4. can 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，它的將來(lái)時(shí)用will be able to; be able to表示主觀意愿，強(qiáng)調(diào)要克服困難去做某事。例如： 1）My grandma is over seventy, but she can still read without glasses. 2）He is able to give up his bad habits. 5. must 和 have to must 和 have to 都可以表示“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)閙ustnt是“一定不要”、“一定不能”的意思。例如： 1）You must come to the classroom before eight. 2）It is raining hard outside, but I have to leave now. 3）“Must we do