情态动词一can_may_must的用法

情态动词can,may,must的用法,情态动词后接动词原形;没有人称和数的变化;不能单独作谓语,与后面的动词共同作谓语;其否定形式在后面直接加not。,Modalverbs情态动词,can/cannotmay/maynotmust/mustnot,Modalverbs情态动词,can/cannot,1.表示能力(会)MarycanspeakEnglish,butshecannotspeakFrench.2.表示允许(可以)也可用could(不是过去式)更委婉Can/CouldIuseyourdictionary?3.表示推测(可能)-通常用于否定形式Hecantbeintheoffice.Isawhimgooutjustnow.,1.S1_Kitty_?S2_.,2.S1_Kitty_?S2_.,Canspell,Yes,shecan,Canadd,No,shecant,may/maynot,1.表示允许(可以)也可用might更委婉May/MightIcomein?2.表示推测(可能)-通常用于肯定形式Shemaybestillwaitingforus.3.表示祝愿Mayyouhaveahappyweekend.,may的用法:,may/maynot,以may开头的疑问句，其否定回答用cant或mustnt。-MayIgohomenow?-Yes,youmay.No,youcant/mustnt.,maynot的用法:,Answers:,1.MayIcarryyourbagforyou?2.MayIopenthedoor?3.MayIgetyouachair?4.MayIswitchontheTV?5.MayIborrowyournewbicycle?,must/mustnot,1.must表示必须Youmustdoyourhomeworkfirst.2.must表示“一定”(肯定性推测)语气较强Hemustbeathome.,must的用法:,must/mustnot,1.mustnt表示禁止(不准；不允许)Youmustntsmokehere.2.以must开头的疑问句，其否定回答要用neednt.-MustIcleantheclassroomnow?-Yes,youmust.No,youneednt.,mustnot的用法:,五.haveto的用法,表示客观需要“不得不，必须”,Imissedthetrain,soIhadtotakeataxi.,在疑问句和否定句中，haveto需借助助动词do，,Didhehavetodoit?,Youdonthavetogothere.（不必，不需要）neednt,六need的用法,后加动词原形表示需要，必须，用于否定和疑问句否定：neednt（不需要），疑问将need提前,注：用于肯定句时，常作实意动词用：needtodosth,Needwereturnthemagazinestoday？yes，youmust./no,youneednt.,Youneednotdothis。,疑问句回答：同must,Whatdothesignsmean?Doyouknow?,Youmustnotcycle.,Youmustbecareful.,Youmustturnleft.,Youmustnotenter.,Youmustpaytenyuan.,Youmustkeepsilent.,Youmustnotturnright.,Youmustnotsmoke.,.用适当的情态动词填空：。1.Icanplayfootball._youswim?2.Dontworry.You_returnmethisbooktomorrow.3.Mygrandmaisill.You_talksoloudlyhere.4.Icantplaywithyou.I_finishmyhomeworkfirst.5.I_getupearlytomorrow.becauseIhaveameeting.6._youpleaseopenthewindow?,Can,may,cant,must,must,Can,9.Nobody_livewithoutair.10._hespeakChinese?Yes,alittle.11.Thebook_bereturnedbeforeSaturday.12._Icomein?Yes,please.13.You_giveupsmokingatonce.Itsbadforyourhealth.14.Excuseme._Iaskyouaquestion?15._youtellmewherethestationis?16._Ifinishtheworknow?No,you_.You_doitthisevening.17.MayIuseyourdictionary?Sorry,you_.Iamusingitnow.18