《If条件句的用法》PPT课件

If条件句的用法theusageofconditional,条件句,条件句（conditional）是由条件状语分句（if分句）+主句构成的复杂句(complexsentence)。一共分为三种(3types)1ifwhenever(themeaningiscloseto)2主将状从现3虚拟,真实条件句,非真实条件句,Thetype1:ifwhenever,Type1是真实条件句（RealConditional）的一种。在这种条件句中，if的意义接近于whenever，所以这种句型又被称为“whenever-型”，可用于3种场合：1、表示普遍真理和客观事实（tellthetruth)Forexample:Ifyoupouroilonwater,itfloats.Ifthetemperaturedropsto0degreesCentigrade,waterfreezes.总结：由上两例可看出，凡表示不受时间限制的自然法则的条件句，其if-分句和主句的谓语动词都用一般现在时：Pattern：（if)simplepresent+(Main)simplepresent,2、表示现在习惯动作Forexample:Ifitrains,Igotoworkbybus.IfImakeapromise,Ikeepit.总结：在上述表示现在习惯动作的条件句中，if-分句和主句的谓语动词也都是用一般现在时：Pattern：（if)simplepresent+(Main)simplepresent3、表示过去的习惯动作Forexample:IfIwashungry,Iusuallyhadafullmeal.总结：表示过去习惯动作的条件句中，If-分句和主句的谓语动词都用一般过去时。Pattern：（if）simplepast+（Main)simplepast.,Thetype2:主将状从现,Type2是真实条件句的主体，最普遍最常用。（是重点）一、基本形式：(2种）1、if-分句用一般现在时表示将来时间，主句用shall/will/can/may(现在时）Pattern:（if）simplepresent+（Main）shall/will，etc例句：IfIseehimagain,Iwilltellhimwhatyousaid.Whatwillhappeniftheycantreachanagreement?Ifyousetyouralarmclock,youwontbelatetomorrow.,2、if分句用一般现在时表示将来时间，主句用动词祈使式：Pattern:（If）simplepresent+（Main）imperative例句：Ifyouwakeupbeforeme,givemeacall.Ifyougooutthisroom,turnoffthelights.二、变体形式（3种）1、if-分句动词不管主语的人称和数如何，一律用should+不定式，主句动词可根据语义意图采用不同形式。Example：Ifitshouldrainagain,theflowerswillbloom.Ifyoushouldcometomorrow,Iwouldtellyouthetruth.说明：在这里，should仅表示一种不太肯定的婉转口气，并不影响条件的真实性。,2、在if-分句中用“will+不定式”并不单纯表示将来意义，这里的will是个表示“意愿”的情态助动词=bewillingtoexample:Ifyouwillreserveseats,weshallbesureofacomfortablejourney.3、用would还是表示“意愿”，常用于客气的请求，这时，主语动词既可用will/shall+inf.也可用would/should/could/might+inf.Example:IfyouwouldtryItalianfood,youwouldlikeit.,注意：省略了to,willingtoreserve,虚拟（第三条件句第四条件句）,这种是非真实条件句（unrealconditional)的一种。所谓“非真实条件”，在语义上包含着不同程度的“非真实性”。这种类型的条件句也可分为基本形式和变体形式。,虚拟,基本类型（if）simplepast/were+(main)would(could,might,etc)+inf例如Ifwecaughtthe10oclocktrain,wewould(could,might,ect)gettherebylunch-time.主句动词都用wouldcouldmight,etc不定式。但可能性的程度不一样IfIknewhowitworked,Icouldtellyouwhattodo.(条件与现实相反，根本不可能告诉对方做什么）,虚拟,这种句型的动词形式还可根据语义意图采用进行体形式。Ifwewereonholidaynow,wedbehavingawonderfultime,虚拟,变体形式(If)wereto+inf+(main)would,etc+inf例：Ifourtrainweretoarrivepunctually,weshouldhavetimetovisityoursister.要注意表示非真实条件的wereto与表示“义务”（obligation）的am/is/areto和was/wereto的区别,虚拟,Ifheweretogetintouchwithme,Icouldexplain.=Supposinghegotintouchwithme.(非真实条件）Ifhewastogetintouchwithme,whyhasnthedoneso?=Ifthearrangementwasthatheshouldgetintouchwithme,why.?(表示“义务”）里一个变体是在if-分句中用would+不定式表示不大可能实现的意愿Ifyoudcookthedinner,iddothewashingupafterwards.（省略to),虚拟,(If)had+-ed分词+Mainwould(couldmight,ect)have-ed分词例如Ifwehadcaoughtthe10oclocktrain,wewouldhavegottherebylunch-time.Wewould/could/mighthavecalledyouifwehadknownyourtelephonenumber,虚拟,如果句子的前半段（if-分句）是表现现在不大可能实现的条件，而后半段（主句）却表示与过去事实相反的情况，前后在逻辑意义上不相协调。但在保证句子合乎逻辑的前提下，也可根据语义意图混合实用俩种句型的动词形式Ifhehadwantedtodance,Idhavetakenhimtodiscotheque(迪斯科舞厅）,虚拟,第四条件句的变体形式（If）weretohave+-ed分词+Mainwould(could,might,ect)have-ed分词例如Ifyouweretohaveaskedme,Iwouldhavebeenonlytoowillingtohelp.,虚拟,30分,20分,40分,10分,10分题,Iusedtowalktowork.Butifit_(rain),Iwentbybus.rained,20分题,Ifyoumovetoyourleft,you_(be)abletoseethechurch,willbe,30分题,Hecouldrepairtheroofhimselfifhe_(have)alongladder.had,40分题,Ifthestoryhadntbeenture,thenewspaper_(notprint)it.wouldnthaveprinted,congratulations!,ifiwereaboybeyonce,IfIwereaboyEvenjustforadayIdrollouttabedinthemorningAndthrowonwhatIwantedthengoDrinkbeerwiththeguysAndchaseaftergirlsIdkickitwithwhoIwatedAndIdnevergetconfrontedforit.Causetheydstickupforme.,IfIwereaboyIthinkIcouldunderstandHowitfeelstoloveagirlIswearIdbeabetterman.IdlistentoherCauseIknowhowithurtsWhenyoulosetheoneyouwantedCausehestakenyouforgrantedAndeverythingyouhadgotdestroyed,IfIwereaboyIwouldturnoffmyphoneTellevveryoneitsbrokenSotheydthinkthatIwassleepinaloneIdputmyselffirstAndmaketherulesasIgoCauseIknowthatshedbefaithfulWaitinformetocomehome(tocomehome),ItsalittletoolateforyoutocomebackSayitsjustamistakeThinkIdforgiveyoulikethatIfyouthoughtIwouldwaitforyouYouthoughtwrong,ButyourejustaboyYoudontunderstandYeahyoudont