情态动词讲解VIP免费

高一英语情态动词1.can(1.)能力HecanspeakfluentEnglish.区别can与beableto的用法：①can只有一般现在时与一般过去时；beableto有各种时态②beableto表示经过努力设法做成某事，相当于managetodo/succeedindoingEveryonewasabletoescapefromtheburningbuilding.(2.)客观可能性（肯定句）“有时会”Itcanbequietcoldhereatnight.(3.)请求许可could（委婉语气）CanIhavealookatyournewpen?--CouldIuseyourcomputertomorrow?--Yes,youcan./No,I’mafraidnot.(4.)用在否定句、疑问句中表怀疑，惊讶等Canitbetrue?Howcanyoubesocrazy?can’thelpdoingsth.忍不住做某事，情不自禁做某事Ican’thelpthinkingheknowsmorethanhehastoldus.cannot/never…too再…也不为过，越…越好Youcannotbetoocarefulwhenyoudriveacar.2.may(1.)请求许可might（委婉语气）--MayIsmokehere?--Yes,youmay./No,youmustn’t.(2.)可能性Johnisabsent.Hemaybeill.Itmaybenottrue./Itcan’tbetrue.(3.)用于祈使句中表祝愿Mayyousucceed!may/mightaswell(dosth.)做某事倒也无妨，只好做某事Ifnooneelsewantsit,wemightaswellgiveittohim.maywelldosth.完全可能Theymaywellwin.3.must(1.)必须Soldiersmustobeyorders.区别must与haveto的用法：①must表示主观看法，haveto表示客观需要IfeelImustcallyoutothankyouforyourhelp.It’srainingheavily.Youhavetotakeanumbrella.②must无时态变化，haveto的时态随have的变化③否定形式的含义不同：mustn’t表示禁止，don’thaveto表示不必Youmustn’ttakethebookoutofthereadingroom.Youdon’thavetotellhimthetruthifyoudon’twantto.④回答must问句--Mustwehandinourexercisebooktoday?--Yes,youmust./No,youdon’thaveto/needn’t.(2.)偏偏，偏要Mustyoushoutsoloudly？Ifyoumust(dosth.)（表示虽不赞同但可允许）如果你一定要做某事1--MayIsmokehere？--Ifyoumust,chooseaseatinthesmokingsection.归纳：can,could,may,might,must都可以表推测肯定句→must,may,might否定句→can’t,couldn’t（不可能）,maynot（可能不）疑问句→can,could情态动词+do/be表现在情态动词+bedoing表现在进行、将来情态动词+havedone表过去如何运用在反意疑问句中：反意疑问部分中的助动词必须根据陈述句中去掉表推测的情态动词，改为陈述客观事实的陈述句中的谓语动词来判断（可根据时间状语）。(1.)Hemayknowtheplan,________________?(2.)Hemusthavelivedhereforalongtime,____________________?(3.)Hecan’thaveleftyesterday,___________________?4.shall(1.)用于一、三人称，表征求对方意见Henryiswaitingoutside.Shallhecomein,sir?(2.)用于二、三人称，表说话者对主语的命令、规定、允诺、威胁、决心等Thestudentsshallwearuniforms.Youshallgetananswerfrommetomorrow.5.should(1.)应该，表示劝告、建议，相当于oughtto（语气稍强，客观情况）Asstudents,weshouldworkhard.Everycitizenoughttoobeythelaw.(2.)按道理应当Therearemanyhotelsthere.Thereshouldn’tbeanydifficultiesforyoutofindone.(3.)用于表示感情的形容词后的that从句中表竟然Itisastonishingthatheshouldbesorudetoyou.(4.)在why,how,who,what+shouldsb.do结构中表惊讶，恼怒等WhyshouldIhelphim?He’sneverdoneanythingforme.(5.)（表示可能）万一，假如Thecompanyguaranteedfreeafter-salesservice，shouldtheirproductshaveanyriskinsafety.Ifyoushouldchangeyourmind,doletmeknow.6.will(1.)意愿（现在）would（过去）Ifyouwilllistentome,I’llgiveyousomeadvice.Theywouldn’tlethiminbecausehewaspoorlydressed.(2.)用于第二人称，表请求would（委婉语气）Will/Wouldyoupleasepassmethebook?(3.)习惯性动作（现在）would（过去）Fishwilldiewithoutwater.Whenweworkedinthesameoffice,wewouldoftenhavecoffeetogether.区别would与usedtodo/be的用法：would表示过去反复发生的动作，与现在无关；usedtodo/be表示过去的状态，强调现在与过去的对比。2Heusedtobeanaughtyboy.Whenhewasyoung,hewouldsmo...