2、Wecanalsouse may and could toaskforandgivepermissionbut can isusedmoreoften.ProhibitionBoth can’t and mustn’t areusedtoshowthatsomethingisprohibited–itisnotallowed.·Youcan’tparkhere,sir.·Youcanwearjeansbutyoucan’tweartrainersinthatbar.·Youmustn’tspeak
3、whentheteacherisspeaking.Can’t tellsusthatsomethingisagainsttherules. Mustn’t isusuallyusedwhentheobligationcomesfromthepersonwhoisspeaking.ObligationHaveto and must arebothusedtoexpressobligation.Thereisaslightdifferencebetweenthewaytheyareused.Havet
7、usemodalverbstosayhowsureweareaboutsomething.1mustWeuse must whenwefeelsurethatsomethingistruebecausethere’sverystrongevidence.·Hemustlivenearherebecausehecomestoworkonfoot. Wedon’tknowwherehelivesbutwe’resureit’snotfaraway.·Comeinsideandgetwarm–youmu
8、stbefreezingoutthere.·You’reazookeeper?Thatmustbeveryinteresting.Noticethat must isfollowedbyaninfinitivewithout‘to’.2might,may,couldWeuse might, may or could tosaythatwethinksomethingispossiblebutwe’renotsure.·Didyouhearthat?Ithinktheremightb