1、Unit2 The correct usage of model verbs.情态动词的用法情态动词的用法目录Warming up 12Presentation3Summary 4Practice Warming up Food is the first necessity of the people.民以食为天。民以食为天。Warming upWhat should we eat to keep healthy?Warming upWe ought to keep the air fresh all the time.Wed better drink more water every day
2、.I think we should eat healthy food every day.meat vegetable fruit snacks(零食小吃)(零食小吃)staple food(主食主食)What kind of food must we eat to be strong and healthy?Warming updiet 日常饮食日常饮食muttonmutton kebabsWarming upmeatcarrotcabbagecucumberpea Warming uptomatolemonwatermelongrapescherryWarming upFruit pot
3、ato chipschocolateIce creamWarming upricedumplingsnoodlesWarming upstaple food主食主食Warming upMust I eat a lot of meat to keep healthy?No,you neednt/you dont have to.PresentationWe ought to keep the air fresh all the time.Wed better drink more water every day.we should eat healthy food every day.Prese
4、ntation情态动词情态动词 should ought to had better must have to need 情态动词是一种本身有一定的词义,表示说情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词。不能单独做谓话人的情绪,态度或语气的动词。不能单独做谓语,只能和其他动词原形构成谓语。语,只能和其他动词原形构成谓语。表示表示“需要,可以,必须,应当需要,可以,必须,应当”。Presentation表示否定的情态动词的用法表示否定的情态动词的用法:mustntneednt shouldnt cant不准不准,禁止禁止没必要没必要(=dont have to)不应该不应
5、该(=ought not to)不能,不可能不能,不可能Presentationought to 和和should ought to 和和should 都为都为应该应该的意思,表示劝告或责任,后者的语气的意思,表示劝告或责任,后者的语气更强一些。口语中也常用更强一些。口语中也常用had better,表示,表示“最好最好(做或不做某事)(做或不做某事)。ought to 的语气稍重一些。的语气稍重一些。should 表示表示主语的义务或责任主语的义务或责任.或指明一个正确、明确的动作。或指明一个正确、明确的动作。You should/ought to do as you are require
6、d.PresentationYou should look after your sister.You ought to follow your teachers advice.They shouldnt be allowed parking here;the street is too new.Presentation多数情况下,多数情况下,ought to 可与可与should 互换使用。互换使用。ought to do反意疑问句用反意疑问句用shouldnt 替代。替代。must 和和have to must表示主观的义务和必要,主要用于肯定句和疑问句中,意思表示主观的义务和必要,主要用
7、于肯定句和疑问句中,意思是是“必须必须.,得,得.;由由must引起的疑问句,肯定回答要用引起的疑问句,肯定回答要用must或或have to,否定回答用否定回答用neednt 和和dont have to,意思是意思是“不必不必”,must的否定形式的否定形式mustnt 表示禁止,意思是不能表示禁止,意思是不能,不许不许Presentationmust 或或 have to 表示表示“必须必须”,not have to 和和neednt 表示表示“不必要不必要”。“过去不必要过去不必要”用用didnt have to 表示。表示。Presentationmust 和和have to Mus
8、t I eat a lot of meat to keep healthy?No,you neednt/you dont have to.have to 的否定形式的否定形式must 的否定形式的否定形式must还可以表示推测,意思是还可以表示推测,意思是一定,想必一定,想必“,即最有可能,但,即最有可能,但却仍是一种主观推测,而不是客观的事实,其否定式用却仍是一种主观推测,而不是客观的事实,其否定式用“cant”.You must be very hungry after you long walk.The phone is ringing but there is no answer.Sh
9、e cant be at home.Presentationmustnt 表示表示“不许,一定不要不许,一定不要”语气很强。语气很强。You mustnt smoke here.can/cant 可以表示能力,也可以表示可能。可以表示能力,也可以表示可能。表能力:表能力:He can(not)speak French.表可能时表可能时can常用于疑问句或者否定句中常用于疑问句或者否定句中Can the news be true?Presentationmust 表示表示主观需要主观需要,而,而have to 表示一种表示一种客观需要客观需要,意思是,意思是“不得不不得不”I have to a
10、ttend an important meeting this afternoon.have to的否定形式是的否定形式是dont have to.They dont have to buy a computer at present.Presentationneednt.1.It must have rained last night,for the ground is wet.昨天一定下雨了,因为地面还是湿的。昨天一定下雨了,因为地面还是湿的。2.I dont know.He may have got lost.我不知道,他可能迷路了。我不知道,他可能迷路了。A.表示对过去发生的事情进行推
11、测表示对过去发生的事情进行推测。情态动词情态动词+have done 1.must have done 一定做了一定做了.2.cant/couldnt have done 不可能做了不可能做了.3.may/might have done 可能已经做过某事可能已经做过某事1.I neednt have got up so early,today is Sunday.我本不必起这么早,今天是星期日。我本不必起这么早,今天是星期日。2.Look,Tom is crying.I shouldnt have been so harsh on him.看,汤姆哭了,我本来不应该对他如此严厉。看,汤姆哭了,
12、我本来不应该对他如此严厉。B.表示本应该表示本应该/不必做不必做.却却.1.ought to/should have done 本该做却没做本该做却没做.2.oughtnt to/shouldnt have done本来不应该做却做了本来不应该做却做了.3.neednt have done 本不必做却做了本不必做却做了.4.couldnt have done 本来能够做某事而没有做本来能够做某事而没有做.SummarySummary1.情态动词的定义情态动词的定义2.ought to 和和should 的用法的用法3.must和和have to 的用法的用法4 情态动词情态动词+have do
13、ne P r a c t i c e1.-Will you stay for lunch?-Sorry,_.My brother is coming to see me.A.I mustnt B.I cantC.I neednt D.I wont2.-May I pick a flower in the garden?-_.A.No,you neednt B.Not,please.C.No,you mustnt D.No,you wont.B C Practice3.You _ return the book now.You can keep it till next week if you like.A.cant B.mustnt C.neednt D.may not4.John,you _ play with the knife,you _ hurt yourself.A.wont;cant B.mustnt;may C.shouldnt;must D.cant;shouldntC B PracticeThanks for watching