情态动词一can_may_must的用法

一、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。•can/cannotmay/maynot•must/mustnotModalverbs情态动词can/cannot1.MarycanspeakEnglish,butshecannotspeakFrench.(VS:beableto)2.Can/CouldIuseyourdictionary?3.Hecan’t/couldn`tbeintheoffice.Isawhimgooutjustnow.may/maynot1.May/MightIcomein?2.Shemay/mightbestillwaitingforus.must/mustnot1.Youmustfinishyourhomeworkfirst.(VS:haveto)2.HemustbeAmerican.表示推测、可能性，mustcancouldmaymightneed/neednot1.Weneedtohavearest.2.----NeedIcleanmyclassroomnow?----No,youneedn`t.(VS:don`thaveto)may/must/need的一般疑问句及其回答：1.MayI.........?Yes,youcan./Yes,youmust.No,youcan`t.2.MustI.........?Yes,youmust./No,youneedn`t.3.NeedI.........?Yes,youmust./No,youneedn`t.二.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?Youdon‘thavetogothere.（不必，不需要）‖needn’t考虑：haveto与must的区别三、hadbetter的用法•表示“最好......”You`dbettergetsomesleep.hadbetter+（not）dosth.nikⅠ.用适当的情态动词填空：。1.Icanplayfootball.__________youswim?2.Don’tworry.You________returnmethisbooktomorrow.3.Mygrandmaisill.You_______talksoloudlyhere.4.Ican’tplaywithyou.I__________finishmyhomeworkfirst.5.I__________getupearlytomorrow.becauseIhaveameeting.6.______________youpleaseopenthewindow?Canmaycan’tmustmustCan9.Nobody___________livewithoutair.10._________hespeakChinese?Yes,alittle.11.Thebook_________bereturnedbeforeSaturday.12.__________Icomein?Yes,please.13.You________giveupsmokingatonce.It’sbadforyourhealth.14.Excuseme._________Iaskyouaquestion?15.__________youtellmewherethestationis?16._______Ifinishtheworknow?No,you_________.You_______doitthisevening.17.MayIuseyourdictionary?Sorry,you_________.Iamusingitnow.18.Lookattheground.It’sverywet.It_______haverainedlastnight.canCanmustMaymustMayCanMustneedn’tcancan’tmust