语法专项突破系列9

语法专项突破系列9.情态动词和虚拟语气一、情态动词考点19大情态动词的基本用法1.can/could(1)表示能力(could常用于过去的能力)*Thepolicestillhaven’tfoundthemissingchild,butthey’redoingalltheycan.

(2)表示理论上的可能性,“有时候可能会”(用在肯定句中)*Itcanbequitewindythere,especiallyinspring.(3)表示请求和允许,口语中常用could代替can(could用来表示现在,用以委婉地提出请求等,但回答时必须用can)*CouldyoutellmehowIcangettotherailwaystation?(4)表示推测“可能”(用于否定句、疑问句中)*Justbepatient.Youcan’texpecttheworldtochangesosoon.2.may/might(1)表示请求、允许、许可,might比may的语气更委婉*—MayItakethebookout?—I’mafraidnot.(2)表示推测“可能”,可能性比can/could小*—Idon’treallylikeJames.Whydidyouinvitehim?—Don’tworry.Hemightnotcome.Hesaidhewasn’tcertainwhathisplanswere.3.must(1)表示“必须;应该”*—ShallIinformhimofthechangeoftheschedulerightnow?*—Iamafraidyoumust,incasehecomeslateforthemeeting.(2)表示“偏要,硬要”做某事*Ifyoumustgo,atleastwaituntilthestormisover.(3)表示推测,“一定”*—Goodmorning.I’vegotanappointmentwithMissSmithinthePersonnelDepartment.*—Ah,goodmorning.YoumustbeMrsPeter.4.shall(1)用于第一、三人称的疑问句中,表示征求对方的意见*Shallwegotothetheatrebybus?(2)用于第二、三人称的陈述句,表示说话人给对方的命令、警告、允诺或威胁;此外,表示法律、条文中规定必须……时也用shall*—Willyoureadmeastory,Mummy?*—OK.Youshallhaveoneifyougotobedassoonaspossible.5.should(1)表示劝告和建议,作“应该”讲*Youshouldlearnfromeachother.(2)表示惊讶、意外等情绪,意为“竟然”*Itissurprisingthatyoushouldnotknowit!(3)用在if条件句中,表示可能性很小,但也不是完全不可能*Ifyoushouldfailtocome,askMrSmithtoworkinyourplace.6.will/would(1)用于表示意志或意愿*—Whydidn’tyoucometoSimon’spartylastnight?—Iwantedto,butmymomsimplywouldnotletmeoutsolateatnight.(2)表示“请求;建议”。用would比will委婉、客气些*Will/Wouldyoupleasekeepthedooropen?(3)表示习惯,will可以表示现在的习惯,意为“总是;习惯于”。表示过去的习惯性动作用would*Hewouldgetupearlywhenhelivedinthecountry.(4)表示事物的某种性质和倾向,或按规律“注定会”*Oilwillfloatonwater.7.need表示“需要;必要”,用于否定句、疑问句和条件从句中*Ineedn’tworryaboutmyweekend—Ialwayshavemyplansreadybeforeitcomes.8.dare表示“敢;敢于”,主要用于疑问句、否定句和条件从句中,一般不用于肯定句。Idaresay是习惯说法,意为“我想,大概”*Idaren’tcatchthemouse.9.oughtto表示义务,意为“应当”,语气比should强,表示不十分肯定或含蓄的推测,意为“应是,应该”*Yououghttoworkharderthanbefore.【点津】3组易混词(组)用法比较另外要注意:(1)can的一些常用固定搭配cannotbutdosth./cannothelpbutdosth./cannotchoosebutdosth.表示“不得不,只好”cannot/cannever...enough/too再……也不为过(2)may的一些常用固定搭配maywell+动词原形意为“理应,有足够的理由”,may(might)aswell+动词原形意为“还不如,不妨”。(3)mustn’t表示“禁止”“不许做某事”回答用need提问的问句时与回答用must提问的问句时一样,肯定回答用must,否定回答要用needn’t或don’thaveto。【典例剖析】单句改错(2015·全国卷Ⅰ)Wemustfoundways.解题关键:情态动词must后使用动词原形。答案判定:found改为find【高考集训】单句改错/填空1.(2014·全国卷Ⅱ)Wecanlieonthegrassforarest,orsatbythelakelisteningtomusic.(改错)

()sat改为sit2.(2014·全国卷Ⅰ)Youmay____(find)thatyourchildisattractedbyonemorethananother.3.(2015·全国卷Ⅰ)Butyou_____besuccessfulwhenthere’salackoftrustinarelationship.findcan’t考点25大表示推测的情态动词用法比较情态动词适用句式适用时态意义must肯定句一般时、进行时、完成时一定、肯定Jackdescribedhisfather,whomusthavebeenabraveboymanyyearsago,asastrong-willedman.情态动词适用句式适用时态意义can(could)疑问句,否定句一般时、进行时、完成时可能,能够Itcan’tbethepostmanatthedoor.It’sonlysixo’clock.情态动词适用句式适用时态意义may(might)肯定句,否定句一般时、进行时、完成时也许,可能—Ileftmyhandbagonthetrain,butluckilysomeonegaveittoarailwayofficial.—Howunbelievabletogetitback!Imean,someonemighthavestolenit.情态动词适用句式适用时态意义should(oughtto)肯定句,否定句一般时、完成时确定或期待,“应该”Ishouldn’thavewatchedthatmovie—it’llgivemehorribledreams.will(would)肯定句、否定句、疑问句一般时、进行时、完成时大概*Thiswillbethehouseyou’relookingfor.这大概就是你正在找的那所房子了。二、虚拟语气考点1状语从句中虚拟语气的用法1.非真实条件句中虚拟语气的用法if条件从句从句的谓语形式主句的谓语形式表示现在情况动词过去式(be的过去式用were)should/would/could/might+动词原形IfIhadtime,Iwouldgothere.if条件从句从句的谓语形式主句的谓语形式表示过去情况had+过去分词should/would/could/might+have+过去分词Ifyouhadcomeearlier,youcouldn’t/wouldn’thavemissedthebus.if条件从句从句的谓语形式主句的谓语形式表示将来情况should+动词原形should/would/could/might+动词原形动词过去式wereto+动词原形Ifitshouldrain/rained/weretoraintomorrow,thesportsmeetingwouldbeputoff.2.目的状语从句中虚拟语气的用法forfearthat/incase+从句:从句谓语用should+动词原形,意为“以防,万一”。*Wegotupearlyforfearthatweshouldmisstheearlybus.3.方式状语从句中虚拟语气的用法asif/asthough+从句:(1)与现在事实相反,从句用一般过去时;(2)与过去事实相反,从句用过去完成时;(3)与将来事实相反,从句谓语用would/could/might+动词原形。*ShespeaksEnglishasif/asthoughshewereanativeofNewYork.【点津】(1)asif/asthough连接的从句表示很有可能的事实时,不需用虚拟语气。(2)要特别注意一些特殊结构的虚拟语气。①在条件句中的省略如果虚拟条件句中含有were,should,had三个词,可将if省略,把这三个词前置于主语之前,形成部分倒装。*WereIinyourposition,Iwoulddothesame.

②错综时间虚拟句当条件状语从句所表示的行为和主句表示的行为所发生的时间不一致时,这种虚拟条件句称为错综时间虚拟句。动词的形式要根据它所表示的时间做出相应的调整。*Ifyouhadtakenthedoctor’sadvice,youwouldbebetternow.③含蓄虚拟条件句有时假设的情况并不以条件句表示出来,而是暗含在上下文中,如通过介词(短语)with,without,butfor等来表示。*WewouldhaveputJohn’snameontheracelistyesterdaybutforhisrecentinjury.考点2其他从句中虚拟语气的用法1.主语从句中的虚拟语气Itisdesired/suggested/proposed/necessary/important/strange/natural/essential/apity+that从句,从句中的谓语动词用“(should+)动词原形”。*It’sstrangethatshe(should)makesomuchtrouble.

2.宾语从句中的虚拟语气(1)表示“建议,命令,要求”等意义时,宾语从句用“(should+)动词原形”。①坚持:动词insist;②命令:order,command;③建议:动词advise,suggest,propose,recommend;④要求:动词request,require,demand,ask。*Teachersrecommendparentsnotallowtheirchildrenunder12toridebicyclestoschoolforsafety.【点津】①suggest意为“表明,暗示”时,宾语从句不用虚拟语气;②insist意为“坚持说”时,宾语从句不用虚拟语气。(2)Iwish(that)+宾语从句(虚拟语气)。①表示愿望与“现在事实相反”,从句用一般过去时;*Howhewishesthathewereabird!

②表示愿望与“过去事实相反”,从句用过去完成时;*WewishthatwehadvisitedtheGreatWalllastyear.③表示将来愿望实现的可能性很小,从句常用could/would+动词原形。*Wewishwewouldliveonthemoononeday.(3)wouldrather/prefer+that从句(从句用虚拟语气)①表示愿望与“现在事实或将来事实相反”,从句用一般过去时。*Iwouldratheryouwerenotherewithmenow.②表示愿望与“过去事实相反”,从句用过去完成时。*Iwouldratheryouhadn’tdonethat.3.表语从句和同位语从句中的虚拟语气(1)在suggestion,proposal,order,plan,idea,request,advice等名词后的表语从句和同位语从句中要用虚拟语气。其构成是“(should+)动词原形”。*Hegaveordersthattheguests(should)behospitablyentertained.(2)asif,asthough引导的表语从句常用虚拟语气,与现在事实相反用一般过去时;与过去事实相反用过去完成时。*Itlooksasifhewere10yearsyoungertoday.*Itlooksasifhehadn’thadamealforaweek.4.定语