情态动词讲解 最好版

ModalVerbs,can/could1.表示“能力”，此时could是can的过去式与beableto的区别can/could只表示有能力做某事beableto表示有能力做并且确实做到了2.表示惊异、怀疑、猜测（多用于否定句和疑问句中）could/can此时表示语气强弱或可能性大小。Howcanyoubesorude?Michaelcantbeapoliceman,forheismuchtooshort.3.表示“请求、许可”翻译成“可以”此时could语气更委婉。Can/couldIuseyourcartomorrow?Youcanborrowsomebooksfromthelibrary.4.有时会，偶尔会ItcanbequitecoldinMay.,may/might1.表示“请求、许可”，might语气更委婉，此时可与could/can互换MayIaskyouforhelp?2.may放到句首时表祝愿Mayyousucceed!/MayGodblessyou!3.表推测“也许、可能”Hemaycomeheretomorrow.maywelldo很可能may/mightaswelldo最好，不妨,must1.“必须”否定式：mustnt不应该、不许可、不准、禁止Youmusthandinyourhomeworkbeforetheclassisover.neednt/donthaveto“不必”2.肯定式表示对现在或过去的推测，“一定”mustbedoingsth./musthavedonesth.Hemustbewaitingforusnow.Hemusthaveseenthefilm.3.“非得、偏要”（常用于疑问句/条件状语从句中）MustIplaythepianoathome,mum?Ifyoumustknow,hernameisLucy.,must与havetodo的区别:must表示说话人的主观看法“必须”havetodo表示客观上需要，不得不做某事，有人称、数和时态的变化。,shall1.用在一、三人称疑问句中，表示向对方征求意见Shallwebeginourclass?Whenshallhebeabletoleavethehospital?2.用在第二、三人称陈述句中，表示说话人给对方的命令、警告、允诺、威胁。Youshallbepunishedifyoukeeponcomingtoschoollate.Heshallbefired.3.根据某项协议规定“应该”Youshallbringdownthepriceaccordingtotheagreement.,should/oughtto1.表示责任或义务上“应该”oughtto的语气更强should含有建议、劝告的意味。2.should表推测“应该”3.竟然Icantimaginethatheshouldbehavesorudelyattheparty.4.万一(if条件从句中)Ifthecomputershouldbreakdown,wellattheexpenses.,will/would1.表示“请求、建议”would语气更委婉Will/wouldyoupleaseopenthedoor?Wouldyoupassmethebook?2.表示意愿、意志和决心。此时would是will的过去式Iwillneverdothatagain.Hesaidhewouldhelpusoutoftrouble.3.would表示过去经常发生或习惯性的动作，“总是”Hewouldgoswimminginsummerwhenhelivedinthecountryside.usedtodo过去常常但现在已不再,need/dare情态、实义动词need必须、需要（常用于否定和疑问句中）dare敢（常用语否定、疑问和条件句中）needtodo/daretodo有人称、数和时态的变化Idaresay我敢说，我认为,情态动词+havedone表示推测和虚拟1.musthavedone只用于肯定句中，表示对过去情况肯定的推测2.shouldhavedone_3.shouldnthavedone_4.can/couldhavedone_,表推测，过去应该做了某事,表虚拟，过去本应该做某事而实际没有做,表推测，过去不应该做了某事,表虚拟，过去本不应该做某事而实际上做了,表推测，过去可能做了某事,表虚拟，过去本来有能力/能够做某事而没有做,5.cant/couldnthavedone_6.may/might(not)havedone_7.neednthavedone_didntneedtodowouldhavedone本来会去做,表推测，过去不可能做过某事,表推测，过去也许/或许(没)做了某事,表虚拟，过去本可以/可能做某事而实际没有做,本来没有必要做某事,1.Oneofthefewthingsyou_sayaboutEnglishpeoplewithcertaintyisthattheytalkalotabouttheweather.A.needB.mustC.shouldD.can2.Thebiggestproblemformostplants,which_justgetupandrunawaywhenthreatened,isthatanimalsliketoeatthem.A.shantB.cantC.needntD.mustnt,D,B,3.Hedidntregretsayingwhathedidbutfeltthathe_itdifferently.A.couldexpressB.wouldexpressC.couldhaveexpressedD.musthaveexpress