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if引导的条件句Ifsheinvitesmetomorrow,Iwillgototheparty.请把这句话与下面虚拟语气的带条件从句的主从复合句进行比较：Ifsheinvitedme,Iwouldgototheparty.假如她邀请我参加聚会，我就去。Ifshehadinvitedmeyesterday,Iwouldhavegonetotheparty.假如她昨天邀请我参加聚会，我就去了。Ifsheshouldinvitemetomorrow,Iwouldgotothepart如果她明天邀请我参加聚会，我会去的。•后退一步法是指在准确地判断了该句与哪一事实相反后，if引导的非真实条件状语从句中，谓语动词按正常情况“后退一步”。•也就是：①与过去事实相反，在从句中用过去完成时形式表示②与现在事实相反，在从句中用过去一般时形式表示③与将来事实可能相反，在从句中用过去将来时形式表示•主句中则用情态动词would,should,could等加动词形式if条件句中的谓语动词主句的谓语动词1.行为动词用过去形式2.be动词用wereShould/would/could/might+动词原形1.对现在的虚拟1.Ifthepeoplewerebettereducated,Ibelievethiscouldsolvetheproblem.Iftheyhadpropereducationinschools,theywouldknowhowtocontroltheirlives.if条件句中的谓语动词主句的谓语动词HaddoneShould/would/could/might+havedone2.对过去的虚拟1.Iftheyhadendedtheirmeetingwithoutfurtheraction,Amerciawouldhavebeenverydifferent.Iftheyhadnotcampaginedforfinancialindependence,womenmaynothavehadcontrolovertheirownmoney.if条件句中的谓语动词主句的谓语动词1.行为动词用did2.should+动词原形3.wereto+动词原形Should/would/could/might+动词原形与将来事实相反的假设1.Ifthelectureshouldbelate,youshouldhavetomakeaspeechfirst.2.Ifthelecturewerelatetomorrow,youwouldhavetomakeaspeechfirst.•虚拟语气中省略if：在书面语中，如果从句的谓语中有were,had或should,就可以省略if,并将were,had或should放到句首。当然，如果从句没有were,had,或should,就不能省略if.IfIweretodoit,I`ddoitsomeotherway.→WereItodoit,I’ddoitsomeotherway.Ifyoushouldfail,tryagain.→Shouldyoufail,tryagain.Ifyouhadbeenhereearlier,youwouldhaveseenhim.→Hadyoubeenhereearlier,youwouldhaveseenhim.IwouldhaveboughtthehouseIfIhadhadenoughmoney.→IwouldhaveboughtthehousehadIhadenoughmoney.•Note：省略了if的倒装形式的句首不能用动词的缩略形式。Wereitnotfortheexpense,IwouldgotoItaly.（√）Weren’titfortheexpense,IwouldgotoItaly.（×）•Butforyourhelp,Icouldn’thavedoneit.•Withoutelectricityhumanlifewouldbequitedifferenttoday.练习：请用介词短语代替条件状语从句1.要不是你的帮助，我就失败了。2.如果没有恰当的控制手段，核反应堆就会爆炸（核反应堆nuclearreactor）。4.1Wish/ifonly的用法用在“wish+宾语从句”中，表示很难实现或不能实现的愿望，可以翻译为“但愿…”,“悔不该…”等。①表示对现在的虚拟，从句的谓语动词用过去式（be动词用were）；②表示对过去的假设，从句的谓语动词用“had+过去分词”③表示对将来的愿望，从句的谓语动词用“would(could)+动词原形①表示与现在事实不相符的假设事件1.V-ed主语+wish/ifonly+that+2.were3.would/could/should+V•Iwishthatheweremyboyfriend.•Iwishthathecaredforme.•IwishthathecouldhelpmewhenIanintrouble.②表示与过去事实想法的假设主语+wish/ifonly+that+1.过去完成时2.would/could/should+V+havedone•Iwishthathehadbeenmyboyfriendatthattime.•IwishthatshecouldhavehelpedmewhenIwanintrouble.③与将来事实相反主语+wish/ifonly+that+would/could/might+动词原形•Iwishyouwouldagreewithme.•Ifonlytherainwouldstop.•IwishIcouldseethesituationthroughhiseyes.注意：wish与hope接宾语从句的区别在于：hope表示一般可以实现的希望，宾语从句用陈述语气。Wish表示很难或不大可能实现的愿望，宾语从句用虚拟语气。请比较：•Wehopewewillsucceed.(Wedon’tknowifwewillsucceed.)•Wewishwewouldsucceed.(Weknowwecanhardlysucceed.)4.2asif/asthough,evenif/eventhough从句中的虚拟.①如果指的是现在的状况，则用过去式(be用were)②如果指过去发生的动作，则谓语动词用had＋过去分词形式③如果指将来的事情，would(should,could)+动词原形•Shelooksasif/thoughshewereill.看她的样子，好像生病了。•Hewalksasifhewereaking.他走起路来就好像他是国王。•Heactedasifnothinghadhappened.他表现得若无其事。•Hewouldnotresigneveniftheheavenshouldcollapse.即使天塌下来，他也不会辞职。4.3在Itis(high)time(that)…句型中①后面的从句的谓语动词常用过去式(be的过去式用were)②或用should+动词原形(should不能省略)来表示。这句话的意思是“（现在）该…”。Forexample:•Itistimeweleft/shouldleave.•Itishightimethatyougotmarried.•ItistimethatIboughtacar.4.4在Iwouldrather(that)…句型中,“我宁可…”Wouldrather+从句+与现在事实相反，则用过去式(be用were)Wouldrather+从句+与过去动作相反，则谓语动词用had＋过去分词形式Forexample:•I’dratherIwereintherainnow.•I’dratheryoudidnottellhim.•Iwouldrathershehadn'tdonethat.4.6用在表示建议、要求、命令等意思的动词主语+谓语动词+should+动词原形，should可以省略。这类的动词有：arrange/command/demand/desire/insist/order/propose/request/require/suggest/beg/move（提议）•Wesuggestedthatwe(should)haveameeting.•Weinsistedthatthey(should)gowithus.•Thedoctororderedthatshe(should)stayinbedforafewdays.•Hedemandedthatwe(should)startrightaway.•Thevillagersrequestedthattheoldbuildingnotbepulleddown.Note：suggest表示“暗示，表明”时，宾语从句不用虚拟语气。Insist后面强调的是事实时，宾语从句也不用虚拟语气。Note:若上述表示建议、要求、命令等意思的动词用作名词时，名词之后的从句用虚拟语气，should可以省略。如：Hemadearequestthathe(should)beallowedtotake3daysoff.Oursuggestionisthateducationnotbeindustrialized.•Note:上述动词在Itissuggestedthat…,Itisrequiredthat…,It’srequestedthat…,It’sorderedthat…,It’sarrangedthat…句型中，that之后的从句用虚拟语气，should可以省略，但引导词that不能省略。如：•Itwassuggestedthatheattendtheconference.•Itwasrequestedthatthetrialbeopenlyreported.4.7用在表示建议、要求、命令等意思的形容词在It’simportant(imperative,necessary,essential,vital,desirable,advisable,better)that…句型中，that引导的从句用虚拟语气，should可以省略。这个句型表示说话人的意见、要求等。Forexample:•Itisessentialthatthereshouldbeenoughfoodandclothingforthewinter.•ItisdesirablethatyourweddingbepostponeduntilnextJuly.•Itisimperativethattheboardchairmanbepresentattheboardmeeting.•总结：在学习虚拟语气的时候要善于发现虚拟语气的规律。根据动词的变化，大致可以把虚拟语气分为三种：①if…,wish,suppose的情况，动词用过去式，过去分词式，或过去将来式②表示建议、要求、命令等意思的动词或名词后面所接的从句，以及Itisimportant(necessary)that…后面所接的从句①Itis(high)time(that)…和Iwouldrather后面的从句，动词用过去式或过去进行时