1、Healthy eatingUnit 2第二课时 Learning about Language情态动词()Unit 2课堂要点探究 2课堂达标验收 3课前新知预习 1课 时 作 业 4课前新知预习 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
2、_，表示对_的肯定推测)He could not believe his eyes.(could意义：_，强调_)答案：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；能力课堂要点探究 一、基础点拨 1ought 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
3、.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
4、吧？2have to的用法 have to“不得不”。有时态、人称和数的变化，其否定形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 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。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 名师点拨 have to的否定式为dont have to，表示“没有义务
5、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mustnt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。3need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
6、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
7、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，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
8、也没来)neednt havedone表示过去本来没必要干某事而实际上却干了。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 1must 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。2can 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 ba
9、g is still in the room.他绝不可能走了。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)3should(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
10、。(却告诉了他)4may/might have 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。5neednt 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 1Its quite warm here;we_ turn the heating on yet.答案：neednt 句意：这儿非常暖和；我们不必开暖气。
11、2Happy birthday!Thank you!Its the best present I _have wished for.答案：could 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。3May I take this book out of the reading room?No，you_.You read it in here.答案：mustnt 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。4Jack described his father,who_have
12、been a brave boy many years ago,as a strongwilled man.答案：must 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。5Doctors say that exercise is important for health,but it_be regular exercise.答案：must 句意：医生说锻炼对身体很重要，但是必须是经常锻炼。must“必须”。6We _ have bought so much food now that Suzie wont be
13、 with us for dinner.答案：neednt 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。7I_have watched that movieitll give me horrible dreams.答案：shouldnt 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”。8He did not regret saying what he did but felt that he _have expressed it differently.答案：could 表示过去本
14、可以做到某事，应用could have done结构。9What sort of house do you want to have？Something big?Well,it_be bigthats not important.答案：neednt 本题考查情态动词的用法。句意为“你想要什么样的房子？大的吗？”“噢，大可不必那不重要”。10Im sorry.I_ not have shouted at you the other day.Forget it.I was a bit out of control myself.答案：should 由第一个人说的话可知说话人为过去(the othe
15、r day“几天前”)做的事情后悔，即“过去做了不应该做的事情”。11Hows your tour around the North Lake?Is it beautiful?It_be,but it is now heavily polluted.答案：should 根据语义应填should“应当；应该”。12She looks very happy.She_have passed the exam.I guess so.Its not difficult after all.答案：must must have done sth表示对过去事情的肯定推测。13I told your frien
16、d how to get to the hotel,but perhaps I_have driven her there.答案：should should have done sth表示“过去本应该做某事而实际未做”。14My MP4 isnt in my bag.Where_I have put it?答案：can can用于否定句和疑问句中表推测。15Where is my dictionary?I remember I put it here yesterday.You_ have put it in the wrong place.答案：might 对过去可能发生的事情的推测用might have done。
