《综合英语》课件-IF条件句精讲

IF条件句if引导的条件句if引导的条件句表示在某种条件下，会导致另一事发生。句式为if从句+主句。中文意思是“如果某事发生（或不发生），另一事就（不）发生”。通常分以下两种情形：一、真实条件句二、虚拟条件句一、真实条件句if从句用一般现在时，主句用一般将来时，表示从句中的动作如果发生，那么主句中的动作也将发生。如：

Ifitstopsraininglaterthisafternoon,wewilleatout.2.if从句和主句都用一般现在时，表示客观真理或习惯和持续发生的事情。如：

Ifthemoongoesneartheearth,thetidegoeshigh.3.if从句用一般现在时，主句用祈使句，表示给某人提建议或命令某人做某事，及提出建议或请求。如：

Ifyouarenotlikelytobeintown,pleaseletmeknow.

二、虚拟条件句虚拟条件句，也称非真实条件句，表示在某种假想的条件下，将导致某事发生。从句中所陈述的事情仅仅只是说话者的想法，不是事实，也不可能发生。

虚拟语气是一种特殊的动词形式，表示所说的话不是一个事实，而只是一种假设，愿望，建议，怀疑，猜测或不大可能实现的空想。IfIhavetime,Iwillgowiththem.(陈述语气)IfIwereyou,Iwouldgowiththem.(虚拟语气)I.虚拟语气用在条件状语从句中虚拟语气用在条件状语从句中，通常从句由连词if引导。1.与现在事实相反的虚拟条件句

IfIfeareddeath,Iwouldn’tbeaPartymember.怕死就不做共产党员。Iftherewerenoair,wecouldn’tlive.如果没有空气，我们就不能生活。条件状语从句主句If+主语+动词过去式(be的过去式用were)主语+would,should,could,might+动词原形

1.IwouldaskGeorgetolendusthemoneyifI______him.A.hadknown

B.knew

C.haveknown

D.know2.I_____ittohimifIthoughthewouldunderstand.shallexplain

B.willexplain

C.wouldexplain

D.explain2.与将来事实相反的虚拟条件句构成

Ifheweretocometomorrow,thingswouldbeeasier.假如他明天会来，事情就容易办了。条件状语从句主句If+主语+wereto/should+动词原形If+主语+动词过去式(be的过去式用were)主语+would,should,could,might+动词原形Ifthesea____torise50feet,Indiawouldbecomeanisland.A.will

B.is

C.was

D.wereIfyou____seeMary,whatwouldyoutellher?A.are

B.willbegoing

C.must

D.should3.与过去事实相反的虚拟条件句构成例如Iftherehadbeennoairinthetube,theresultwouldhavebeenbetter.条件状语从句主句If+主语+动词过去完成式主语+would,should,could,might+have+过去分词Ifyouhadn’tgonewithTomtothepartylastnight,_______.A.youwouldmeetJohnalready

B.youwon’thavemissedJohnC.youwillhavemetJohn

D.youwouldhavemetJohn4.省略连词if在条件状语从句中，如果有were,should,had，可以把连词if省去，把were,should,had放在句首，构成条件意义。例如：Ifitshouldraintomorrow,whatwouldyoudo?Shoulditraintomorrow,whatwouldyoudo?Ifwehadknownaboutthenewmethod,weshouldhaveapplieditearlier.Hadweknownaboutthenewmethod,weshouldhaveapplieditearlier.HadAlicebeenmorehardworking,she_______.A.hadnotfailed

B.wouldnotfailC.couldnotbefailed

D.wouldnothavefailed_______today,hewouldgettherebyFriday.A.Wouldheleave

B.WasheleavingC.Werehetoleave

D.Ifheleaves______difficulties,wewouldbesuccessful.A.Shouldweovercome

B.WouldweovercomeC.Mightweovercome

D.Couldweovercome5.虚拟结构中省略主句或从句虚拟结构中有时可省去主句或从句，并不影响意义的完整。(1)省去条件从句Thatwouldbefine.那太好了。（省去了ifyouwouldco