情态动词can/could表示能力HecanspeakalittleJapaneseinadditiontoEnglish.Mancannotlivewithoutair．Canyoufinishthisworktonight?表示许可Youcan(not)havethebook.CanIuseyourphone?could也可表示请求，语气更委婉，主要用于疑问句，不可用于肯定句，答语应用can(即：could不能用于现在时态的简略答语中)，如：--Couldlcometoseeyoutomorrowmorning7--Yes，youcan.(否定答语可用No，I'mafraidnot．)Couldyouplease…?CouldIuseyourdictionary?---Yes,youcan.c.有时候会Heisabad-temperedfellow,butsometimeshecanbecharming.Theycanbeveryvaluable.d.在否定句和疑问句中表示猜测(can’t不可能)Someoneisknocking.Whocanitbe?Itcan’tbeMr.Li.Becauseheisawayonbusiness.不可能，肯定不Itcan’thaverainedlastnight,foritisdryoutside.e.与possibly连用;用于as…asonecanCan/couldsb.possiblyCanhepossiblycome?Whatonearthcanshepossiblymean?IwillcomebackassoonasIcan.Sb.can't/couldn'tpossibly某人不可能Ican'tpossiblyallowyoutogohomeinthisweather.f.表示惊异，怀疑不相信的态度．(主要用在否定句、疑问句或惊叹句中)如：Canthisbetrue?Howcanyoubesorude!ThiscannotbedonebyMary.Howcanyoubesorude!注意：can与beableto区别：can表能力，只用一般过去时和一般现在时beableto表能力+成功，即最终设法做成了某事。有各种时态,可以与别的情态动词连用。Thefirespreadthroughthehotelveryquickly,buteveryone______getout.（NMET97）A.wasabletoB.couldC.hadtoD.wouldg.固定句型cannot…too/cannever…too再也不过分Youcanneverbetoocareful.Wecanneverattachtoomuchimportancetobalanceddiet.2.may/mighta.表示允许,might语气更委婉在表示请求、允许时，might比may的语气更委婉一些，否定回答时要用mustn't，表示"不可以"、"禁止"、"阻止"之意．如：Youmaydrivethecar．--Mightluseyourpen?--No，youmustn't.用MayI．．．征询对方许可在文体上比较正式，在口气上比较客气。在日常口语中，用CanI．．．征询对方意见更为常见。MayIuseyourruler?---Yes,helpyourself./Yes,youmay.---No,youmustn’t.b.表示可能性,might语气更弱Hemayfeelbored.Hemayhavereaditbefore.c.用于祈使句中表示祝愿。如：Mayyousucceed!MayGodblessyou!d.用于目的和让步状语从句中，表强调Imaybeslow,butatleastIdon’tmakemistakes.Writetohimatonce,sothathemayknowitintime.e.固定搭配：may/mightaswell不妨，还不如There’snobus.Wemayaswellgohomeonfootnow.maywell很有可能Whatyousaymaywellbetrue.f.用于虚拟语气中Hadtheyknownwhatwascomingnext,they_______secondthoughts.(2012浙江高考19)A.mayhaveB.couldhaveC.musthavehadD.wouldhavehad3.will/would表示将来时Hesaidhewouldwaitforme.表示请求或建议,would语气更委婉W