if条件句中的时态应用

if条件句中的时态应用if是高考考查热点之一。同学们往往把它的时态容易判断错误。笔者就if中的时态应用总结如下：一．意“如果”表真实条件。引导真实条件句。从句要求用一般现在时表将来。Ifitrainstomorrow,we`llstayathome.如果明天下雨的话，我们将呆在家里。Iftheycometomorrow,we`llhaveameeting.如果他们明天来的话，我们就开个会。注意：在表示“愿意”或“不愿意”时，if后可以跟will或won’t.。如:Ifyouwon’tgo,I’llgoalone.如果你愿意去，我就自己去。二．意“假如”表虚拟条件。引导虚拟条件句。表示与事实相反的假设。虚拟条件句和主句的时态构成如下：虚拟情况从句时态主句时态与现在事实相反一般过去时(be用were)would(should,could,might)+动词原形与将来事实相反一般过去时(be用were)should+动词原形wereto+动词原形would(should,could,might)+动词动词原形与过去事实相反过去完成时would(should,could,might)+have+过去分词IfIwereabird,Icouldflyintheair.如果我是一只小鸟，我就会在天上飞。IfIhadenoughmoneynow,Iwouldlendittoyou.如果我现在有足够钱的话，我就会借给你。Ifitshouldraintomorrow,theracewouldbeputoff.如果明天下雨的话，比赛就会推迟。Ifyouhadarrivedearlierthatday,youmighthavemether.如果那天你早点到的话，你就会遇见她了。三．意“是否，是不是”引导间接问句。当主句为现在时时，从句应用适当的时态。当主句为过去时时，从句应当遵循时态一致的原则，要采用相应的过去时态。Idon’tknowiftheywillcometomorrow.我不知道他们明天是否会来。Heaskediftheywouldcomethenextday.他问他们第二天是否会来。注意：在正式的文件中，若句中有助动词had、were、should，则将其提前，省略if.Haditnotbeenforyourhelp,wewouldnothaveachievedsomuch.要不是你的帮助，我们不会取得如此大的成绩。四．固定搭配：①ifonly:意“要是……就好了”，表示一种不真实的条件。其后接从句。从句用虚拟语气。用一般过去时表示现在没有实现的愿望；对过去没有实现的愿望从句用过去完成时。IfonlyIhadtakenmother’sadvice.我要是听妈妈的建议就好了。IfonlyIcouldspeakseveralforeignlanguages.我要是能讲几种外语就好了。区别onlyif::意“只有在……条件下才……”用来加强从句的语气。当其位于句首时，主句用倒装语序。Hewouldsucceedonlyifhetriedhard.→Onlyifhetriedhard,wouldhesucceed.只有他努力他才会成功。②:asif/though意“好象”引导状语从句或表语从句。当从句的内容为不真实情况时要采用虚拟语气。与现在事实相反从句用一般过去时，与过去事实相反从句用过去完成时。与将来事实相反从句用would(could,might)+动词原形Shecriedasifherheartcouldbebroken.她哭得好象心都要碎了。③:evenif意“即使、纵使”连词，引导让步状语从句。Evenifheispoor,sheloveshim.即使他很穷，她仍然爱他。【巩固练习】1．Sheseldom,_____,blamesherfailureonothers.A.ifeverB.ifanyC.ifnecessaryD.ifpossible2.Ihadneverspentamoreworryingday.Itseemed_____thedaywouldneverend.A.asifB.evenifC.assoonasD.aslongas3.Ifaman_____succeed,hemustworkashardashecan.A.willB.istoC.isgoingtoD.should4.Ifit_____tomorrow,we’llgoroller-skating.A.isn’trainB.won’trainC.doesn’trainD.doesn’tfine5.Ithinkitisnecessaryformy19-year-oldsontohavehisownmobilephone,forIsometimeswanttomakesureifhe___homefordinner.(06高考)A.comeB.comesC.hascomeD.willcome6.Intimeofseriousaccidents,___weknowsomebasicthingsaboutfirstaid,wecansavelives.（06高考）A.whetherB.untilC.ifD.unless7.Ifyou____waitoverthereforaminute,Mr.Smith,I’lltellourmanageryou’vearrived.A.mustB.shouldC.willD.can8.____forthedoctor’scarefultreatment,he____tilllastyear.A.Ifitisnot;can’tliveB.Wereitnot;couldn’tliveC.Haditnotbeen;couldn’thavelivedD.Ifitwasn’t;can’tlive9.Itwouldbeimpossibleforhimtoleavehospitaltomorrowifhe___firstaidwhentheaccidenthappened.Ahadn’tbegivenB.wasn’tbegivenC.shouldn’tbegivenD.wouldn’tbegiven10.IfI___plantodoanythingIwantedto,I’dliketogotoTibetandtravelthroughasmuchofitaspossible.（05高考）A.wouldB.couldC.hadtoD.oughtto答案：1A2A3B4C5D6C7C8C9A10B