人教版高中英語必修三Unit2HealthyeatingGrammar情態(tài)動詞（Modalverbs）一、教學(xué)設(shè)計【教學(xué)目的】Studentswillknowtheusageofthemodalverbs.Studentswilllearntousethemodalverbs.【教學(xué)流程】Step1oughtto與oughtnotto的用法1.oughtto多表示責(zé)任、義務(wù)，語氣強烈，與should意義相近，但should常表示勸告、建議、命令。否定形式為oughtnotto。eg.Bynowhisrestaurantoughttobefullofpeople.Yououghtnottogo.2.should和oughtto的不同：1)should,oughtto表示“應(yīng)該”，oughtto表示義務(wù)或責(zé)任，比should語氣重。eg.Ishouldhelpherbecausesheisintrouble.Yououghttotakecareofthebaby.2)表示勸告、建議和命令。should,oughtto可通用，但在疑問句中常用should。eg.Youshould/oughttogotoclassrightaway.ShouldIopenthewindow?Step2haveto和don’thaveto的用法1.must,haveto比較：1)表示必須、必要。eg.Youmustcomeintime.在回答引出的問句時，如果是否定的，不能用mustn’t（禁止，不準(zhǔn)），而用needn’t,don’thaveto（不必）.eg.—Mustwehandinourexercisebookstoday?—Yes,youmust.—No,youdon’thaveto/youneedn’t.2)must是說話人的主觀看法，而haveto則強調(diào)客觀需要。Must只有一般現(xiàn)在時，haveto有更多的時態(tài)形式。eg.Theplayisn’tinteresting.Ireallymustgonow.IhadtoworkwhenIwasyourage.2.must表示推測、可能性（只用于肯定的陳述句）eg.You’reTom’sgoodfriend,soyoumustknowwhathelikesbest.Yourmothermustbewaitingforyounow.Step3mustn’t的用法雖然must是表示“必須”的意思,但是用于否定式時,mustn’t卻表示“不要、不能、禁止”的意思,而不是表示“不必”.這是中考的一個考點.eg.Youmustn’tleavehere.你不能離開這兒.Youmustn’tgoswimmingtoday.今天禁止你去游泳.Youmustn’tdrivesofast.你不能開這么快.Step4needn’t的用法needn’t不需要;不必;強調(diào)客觀條件。常做must問句的回答：eg.MustIfinishmyhomeworktoday?No,youneedn'tYouneedn'tbeoversensitive.Ithasnothingtodowithme.你不必多心，這事與我無關(guān)。Youneedn'ttruckletoyourauntlikethat.youareagrownwomannow.你沒有必要那樣膽小順從你的伯母，你現(xiàn)在是一個成年婦女了。Childrenbelow120cmneedn’tpayfare.120公分以下的小孩不必買票。Practice：Readthesedialoguesandcompletethemwiththepropermodalverbs.JOHN:Weshouldgettothetheaterbyseveno’clock.Whattimedoyouthinkweshouldleave?SARAH:Ithinkwehavetoleavehomeatsixo’clock,orwewon’tarrivethereintime.GEORGE:Idon’tfeelwell.ThedoctortoldmethatIhavetogiveupsmoking.Healsogavemethemedicine.Doyouthinkit’lldomeanygood?AMY:Ifyoufollowthedoctor’sadvice,itwillhelpyou.SALESMAN:Thiscarisoneofthesafestonthemarket.Evenso,youmustn’tbesillyanddrivewithoutwearingaseatbelt.CUSTOMER:Iwillneverdothat!RON:Let’sgotoCarla’spartytonight!TOM:Well,Idon’tmindgoingaslongasIdon’thavetodressup.RON:That’sOK.Youdon’tevenneedtowearatieifyoudon’twantto.SUSAN:DoyouknowwhereAlanis?Ican’tfindhimanywhere.ROBIN:Well,hecouldn’thavegonefar.Hisbagisstillhere.Step5