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1、Healthy eatingUnit 2第二课时 Learning about LanguageUnit 2情态动词()观察句子，写明情态动词 的用法。 By now his restaurant ought to be full of people. (ought to意义：_；此处指_，具有一 定的针对性)What could have happened? (could have done用于_，表示对_的 猜测)Something terrible must have happened. (must have done用于_，表示对_的肯 定推测)He could not believe
2、 his eyes. (could意义：_，强调_)应该按理应当如何疑问句过去发生动作肯定句过去发生动作能够能力一、基础点拨1 ought to的用法(1)ought to“应该”。与should相比较ought to语气重，偏重“责任，义务，道德，法律”等方面。如：To keep fit, we ought to learn more about our body.为了保持健康，我们应该多了解我们的身体。(2)ought to还可表示可能性。如：It ought to be a close game.那很可能是场势均力敌的比赛。名师点拨用 ought to表示推断时，语气较肯定，通常指的是一
3、种合乎逻辑的可能性(与 should表推断时相似)，有时可译为“准是”(但语气比must要弱)。(3)ought to的否定形式为ought not to或 oughtnt to，其一般疑问句形式是将ought置于主语前。You oughtnt/ought not to scold him.你不该责备他。(4)在附加疑问句中，ought(nt) to中的to要省去。在美语中常用shouldnt代替oughtnt。We ought to go now, oughtnt/shouldnt we?我们现在该走了，是吧？2 have to的用法have to“不得不”。有时态、人称和数的变化，其否定形
4、式和疑问形式需要借助助动词do。如：His mother is ill. He has to stay at home to look after her.他妈妈病了，他得待在家里照顾他。易混辨析have to侧重客观需要；有时态、人称和数的变化must说话人的主观看法I have to go now, for my mother is ill.现在我不得不走了，因为我妈妈生病了。I must stop smoking.我一定要戒烟。名师点拨have to的否定式为dont have to，表示“没有义务或没有必要做某事”，意为“不必”，常可以回答must提问的一般疑问句。而must的否定式m
5、ustnt表示“禁止”。They dont have to worry about the nuclear radiation.他们没有必要担心核辐射。You mustnt come here without permission.未经允许，你不能来这儿。3 need的用法(1)need作情态动词时，后跟动词原形，表示“需要，有必要”，无人称和数的变化，多用于否定句、疑问句或条件句中。如：You neednt go there now. 你现在不必去那儿。Need I go there now? 我现在需要去那儿吗？名师点拨由need引导的一般疑问句的肯定回答常用must或have to，否定
6、回答常用neednt或dont have to。Need I hand in my paper now? 我现在需要交上论文吗？Yes, you must./No, you neednt (dont have to)是的，你必须。/不，你不需要。(2)作为实义动词，同其他实义动词一样，可用于各种句式，有时态、人称、数的变化，构成否定句和疑问句时要借助于助动词do。We need to help him.我们得帮助他。We dont need to tell him the truth.我们不必告诉他真相。名师点拨当 need作 “需要”讲时，其后跟不定式的被动形式相当于跟v. ing的主动形式
7、，在这一点上，与want和 require作 “需要”讲时一样。v. ing的主动形式表被动含义，need的动作执行者是动词 ing形式的承受者，因此必须是及物动词的 ing形式，若为不及物动词其后应跟介词。The house needs/wants/requires repairing/to be repaired.这所房子需要修葺。易混辨析试比较： She neednt have come yesterday.她昨天本不必来。(实际上来了) She didnt need to come yesterday.她昨天不必来。(实际上也没来)neednt have done表示过去本来没必要干某
8、事而实际 上却干了。 didnt need to表示过去没必要干某事而实际上也 没有干。二、难点突破情态动词have done的用法1 must have done用于肯定句，表示“过去一定做过某事”。She must have been very beautiful when she got married.她结婚时一定很漂亮。2 can have done一般用于疑问句和否定句中，用于表示对过去所发生事情的推测。could have done用于肯定句时，表示“本有能力做某事而未做”。He cannot have left.His bag is still in the room.他绝不可
9、能走了。他的包还在屋里呢。In my view， this accident could have been prevented.依我看，这次事故本来是可以避免的。(却发生了)3 Should (ought to) have done表示“过去本应该做某事而(实际上)没有做”，含有责备或遗憾的语气；其否定形式表示某种行为不该发生却发生了。They ought to have been more careful.他们本该更小心些。(却没有)You ought not to have told him the bad news.你本不该告诉他这个坏消息。(却告诉了他)4 may/might hav
10、e done表示对过去发生的事情的推测，意思是“也许已经做了某事，可能已经做了某事”，多用在肯定句中，用might时表示语气更加不肯定。She might have taken it home.她可能把它带回家了。5 neednt have done表示“本不必做某事而实际上做了”。He neednt have gone there yesterday.他昨天其实不必去那儿的。(却去了)课堂达标验收1 (2012天津，8)Its quite warm here; we_ turn the heating on yet.A couldnt B mustntC neednt D wouldnt答案
11、：C 本题考查情态动词的用法。句意：这儿非常暖和；我们不必开暖气。couldnt 不可能； mustnt 禁止，不可以；neednt不必；wouldnt将不会。根据句意，C项正确。2 (2012江苏，35)Happy birthday!Thank you! Its the best present I _ for.A should have wished B must have wishedC may have wishedD could have wished答案：D 考查情态动词。句意：祝你生日快乐！谢谢！这是我能想到的最好的礼物。could have done能够做某事；should h
12、ave done本该做但未做；must have done过去肯定做了；may have done或许做了。3 (2010陕西，23)May I take this book out of the reading room?No， you_.You read it in here.A mightntB wontC needntD mustnt答案：D 句意“我可以把书带出阅览室吗？”“不，不可以，你应在这里读”。由句意知，mustnt “禁止，不许”符合句意 。4 (2010安徽，32)Jack described his father, who_a brave boy many years
13、ago, as a strong willed man.A would beB would have beenC must beD must have been答案：D 句意：杰克把父亲描述成一个意志坚强的人，父亲多年前一定是个勇敢的男孩。表示对过去情况的推测，要用must have done结构，故选D。5 (2010辽宁，26)Doctors say that exercise is important for health, but it_be regular exercise.A canB willC mustD may答案：C 句意：医生说锻炼对身体很重要，但是必须是经常锻炼。本题考
14、查情态动词。can表可能，用于否定句中；must“必须”； may“可能”。6 (2012江西，22)We _ have bought so much food now that Suzie wont be with us for dinner.A may notB needntC cantD mustnt答案：B 考查情态动词。句意：既然Suzie不和我们一起吃饭，那么我们本不必买那么多食物。neednt have done本不必做； may not have done 或许没有做； cant have done不可能做； must have done过去肯定做了。7 (2010山东，25)
15、I_have watched that movieitll give me horrible dreams.A shouldntB needntC couldntD mustnt答案：A 考查情态动词。句意：我不该看那部电影的，那会让我做噩梦。shouldnt“不应该”；neednt“不必”； couldnt“不可能”； mustnt不与have done连用。8 He did not regret saying what he did but felt that he _ it differently.A could expressB would expressC could have expressedD must have expressed答案：C 表示过去本可以做到某事，应用could have done结构。9 What sort of house do you want to have？ Something big?Well, it_be bigthats not important.A mustntB needntC cantD wont答案：B 本题考查情态动词的用法。句意为“
