必修三情态动词的用法

必修三第二单元情态动词的用法语法1、重温情态动词的语法特征。2、掌握情态动词oughtto,oughtnotto,haveto,don'thaveto,mustn't,needn't.3、懂得区分should和oughtto,区分needn't和mustn't。情态动词的语法特征：1.情态动词有一定的意义，表示或暗示某种情绪或态度，表示可能、建议、愿望、必要、允许、能力等。但只表示期待或估计某事的发生，不能表示正在发生或已经发生的事情。2.情态动词不能独立使用，必须和实义动词一起构成谓语。3.情态动词没有人称和数的变化，即不随主语的不同而变化。4.有些情态动词,如can、will也有一般式和过去式的变化。但情态动词的“时态”形式并不是时间区别的主要标志。不少情况下,情态动词的现在式形式和过去式形式都可用来表示现在时间、过去时间和将来时间。知识点回顾：1.—______itbeLiPingwhobroketheglass?—No.It______beWuDongwhodidit.A.Can;mustB.Must;needC.May;mustD.Need;can2.—Don’tforgettovisitmewhenyoucometoBeijing.—______.A.Idon’tB.Iwon’tC.Ican’tD.Ihaven’t3.—CouldIuseyourbike?—Yes,surelyyou______.A.mightB.willC.canD.should4.Herbrother______beathomenow,becausehewasseenplayingbasketballinthestadiumjustnow.A.mustn’tB.needn’tC.can’tD.shouldn’t5.—Whencanyougetmycarrepaired?Ineedittomorrowmorning.—It______bereadyby8:00.A.canB.needC.mightD.should温故而知新（一）6.—Areyoucomingfordinner?—I’mnotquitesure.I______gotomyuncle’sinstead.A.mustB.wouldC.shouldD.might7.Don’tbelievehim.Whathesaid______betrue.A.mustn’tB.needn’tC.shouldn’tD.maynot8.—______Igohomenow,sir?—No,you______.Youshouldfinishthecompositionfirst.A.Might;wouldn’tB.May;hadbetternotC.Must;mustn’tD.Need;mustn’t9.—______heuseyourbike?—Certainly.Hereisthekey.A.ShallB.MustC.WillD.Does10.MrBushisontimeforeverything.How______hebelatefortheimportantmeeting?A.wouldB.shouldC.mightD.need温故而知新（二）1、你应该做适当的运动。Youshoulddosomesports.2、你应该慢慢地进食，这样有助于消化。Youshouldeatslowlyandit’sgoodfordigestion.3、你应该保持房间的整洁。Youshouldkeepyourroomclean。should/oughtto“应该”(一）should常表示劝告、建议、命令，与oughtto意义相近，但oughtto多表示责任、义务，语气强烈。反映客观情况或涉及法律义务和规定时一般用oughtto。例如：Youngpeopleshouldlearnhowtousecomputers.（建议）Everycitizenoughttoobeythelaw.（义务）试比较：你应该慢慢地进食，这样有助于消化。Youshouldeatslowlyandit’sgoodfordigestion.你（胃不好），应该慢慢地进食，这样才能消化得好。Yououghttoeatslowlyandit’sgoodfordigestion.你应该帮忙布置饭桌。（能帮就帮）Youshouldhelptosetthedinnertable。（我忙得团团转，或者客人太多）你应该帮忙布置饭桌。Yououghttohelptosetthedinnertable.should/oughtto“应该”（二）1.You________________gototheclassrightnow.2.They_____________cometomorrow.3.Hethoughtthatthey____________takepartinthedesign.4.________wetodoitatonce?5.Accordingtothelaw,you__________helphimgetagoodeducationasyouarehisfather.巩固练习(should/oughtto)should/oughttooughttooughttoOughtoughttomust用来表示“命令”、“推测”等含义。1）表示规定、指令Youmusthaveapassportifyouwanttogoabroad.如果你想出国，你必须有护照。2）表示猜测，语气非常肯定，近乎确定的意味Youmustbeill.Icanseeitfromyourface.你一定是病了，我能够从你的脸色看出来。3)表示“必须”---MustIhandintheexercisetoday?----Yes,youmust.我今天必须交这个练习吗？是的，必须。Idon’tlikethisTVset.Wemustbuyanewone.我不喜欢这台电视机。我们必须买一台新的。must/haveto“必须”(一）表示“必须”这个意思时，must和haveto稍有区别。must着重说明主观看法，haveto强调客观需要，意思是“不得不”。另外，haveto能用于更多时态。Therewasnomorebus.Theyhadtowalkhome.再也没公共汽车了，他们不得不走路回家。IamafraidYouwillhavetowaitawhile.我看你得等一会儿。AteverystepIhadtopullmylegsoutofthesnow.我每走一步都得将双腿从雪中拔出来。注意haveto在疑问句中的位置。如：Doyouhavetogoouttoday?你今天一定得出去吗?Doeshehavetofinishtheworktomorrow?他明天非做完这项工作不可吗?must/haveto“必须”（二）1.Ifyou______go,atleastwaituntiltherainstops.A.canB.mustC.shouldD.would2.Myparentsneverremembermytelephonenumber,andtheyalways____lookitup.A.mustB.canC.shouldD.haveto3.—____itbeLiPingwhobroketheglass?—No.It____beWuDongwhodidit.A.Could;mayB.Can;canC.May;mustD.Can;must4.Imissedthebus,soI___gohomeonfoot.A.mustB.mayC.canD.hadto巩固练习(must/haveto)1.must的否定形式mustnot/mustn't，“不能，不许”。语气比较强烈,表示禁止,不许可。Youmustn’tcomeherewithoutpermission.未经允许，你不能来这儿。Wemustn'twasteourtime.我们不能浪费时间。Passengersmustnotwalkacrosstherailwayline.禁止旅客横穿铁路。Youmustn'tmissthatmodernballet，Itisextremelygood.你可不要错过这个现代芭蕾舞剧，它好极了。Onemustnotdivorceoneselffromthemasses.不能脱离群众。否定形式（一）2.说不必须用neednot/needn't。由must引起的疑问句，肯定回答要用must或haveto,否定回答要用needn’t或don’thaveto,意思是“不必”。—MustIfinishthetaskrightnow?我现在必须完成这个工作吗？—Yes,youmust./Yes,youhaveto.是的。(—No,youneedn’t./No,youdon’thaveto.不，不必。)---Mustwehandinourexercisestoday?---No，Youneedn't.---我们必须今天交练习吗?---不，不必今天交。注意:didn'tneedto则常表示过去未做也勿须做的动作。这时候的need是实义动词。Ididn'tneedtotakeataxi；itisonlyfiveminuteswalktothestation.到车站只须走五分钟，我不需要坐出租汽车。否定形式（二）3.haveto的否定形式是don’thaveto,相当于needn’t。请注意时态。Theydon’thavetobuyacomputeratpresent.他们目前没有必要买电脑。Mr.Johnsondoesn'thavetoworkveryhardtoearnaliving.约翰逊先生不必为了谋生拼命干活。Wewillnothavetogetupveryearlytomorrow.我们明天不必起得很早。Ishallnothavetogototheclinictodayforalittlecough.我今天不必为一点点咳嗽就去诊疗所。注意didn'thaveto常表示过去未做也勿须做的动作。如：Ididn'thavetointerpretitforher，forsheknowsChinese.我勿须为她翻译，她懂汉语。Youdidn'thavetoleavethepartyearlylastnight.昨晚你不必早点离开晚会。否定形式（三）4.ought的否定形式由直接加not构成:oughtnotto/oughtn'ttoYououghtnottofollowmeasIamwrong.因为我错了，你不应该听我的。Thereferencebookoughtnottobeinthereading-room.这本参考书不该在阅览室里。Itoughtnottobesohottoday.It'ssostrange!今天不该这么热。很怪!Heoughtnottobesoobstinate.他不该这样固执。Yououghtn'ttosmokesomuch.你不应当抽烟太多。Yououghtnottohavebeensorude.你不该这样粗鲁。Yououghtnottohavetakenhisskateswithoutaskinghim.你不该没有得到他的许可就把他的冰鞋拿走。否定形式（四）1.Johnny,you______playwiththeknife,you____hurtyourself.A.won't;can'tB.mustn't;mayC.shouldn't;mustD.can't;wouldn't2.Thebosshasgiveneveryoneaspecialholiday,sowe____gotoworktomorrow.A.can’tB.mustn’tC.needn’tD.shouldn’t3.─Whatdoyouthinkwecandoforouragedparents?─You____d