Unit1AnimalsontheFarmLesson4HorsesandRabbits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/cannot•may/maynot•must/mustnotModalverbs情态动词can/cannot1.表示能力(会)MarycanspeakEnglish,butshecannotspeakFrench.2.表示允许(可以)CanIuseyourdictionary?Ican’tfindmine.3.表示推测(可能)----通常用于否定形式Hecan'tbeintheoffice.Isawhimgooutjustnow.may/maynot1.表示允许(可以)MayIcomein?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can't或mustn't。--MayIgohomenow?--Yes,youmay.No,youcan’t.maynot的用法:must/mustnot1.must表示必须Youmustdoyourhomeworkfirst.2.must表示一定(肯定性推测)Hemustbeathome.must的用法:must/mustnot1.mustn't表示禁止(不准;不允许)Youmustn'tsmokehere.2.以must开头的疑问句,其否定回答要用needn't.--MustIcleantheclassroomnow?--Yes,youmust.No,youneedn't.mustnot的用法:Whatdothesignsmean?Doyouknow?Youmustnotcycle.Youmustbecareful.Youmustturnleft.Youmustnotenter.Canyou…?你会/能……吗?Yes,Ican./No,Ican't.是的,我会/能。/不,我不会/不能。Whatcanyoudo?你会/能干什么?Ican…我会/能……Canyouswim?No,Ican't.Yes,Ican.Canyouplayfootball?Yes,Ican.It'seasy!Whatcanyoudo?Icanrunfast!Canyouplayping-pong?Yes,Ican.Thankyou!