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if引导的条件状语从句（一）定义if引导的句子在复合句中表示条件，假如if从句的动作发生，主句的动作就（不）会发生，因此称为条件状语从句。（二）位置if引导的条件状语从句位置灵活，可直接放在主句后面，也可以放在句首。放在句首时，从句后面要用逗号和主句隔开。①IfIhaveenoughmoney,Iwilltravelaroundtheworld.②IwilltravelaroundtheworldifIhaveenoughmoney.（三）用法（1）当主句是一般将来时时，从句用一般现在时。（主将从现）构成条件从句主句时态If+一般现在时主句+shall/will+动词原形例句Ifitrainstomorrow,we’llstayathome（2）当主句是祈使句时，从句也用一般现在时。①Workhard,andyou’llpasstheexameasily.努力学习，你将很容易通过考试。→Ifyouworkhard,you’llpasstheexameasily.②Hurryup,oryou’llmissthetrain.快点儿，否则你就赶不上火车了。→Ifyoudon’thurryup,you’llmissthetrain.（3）当主句含有情态动词时，if引导的条件状语从句通常用一般现在时。Wemuststudyhardifwewanttopassthefinalexam.如果想通过期末考试，我们必须努力学习。（4）用含介词with或without的介词短语转换。①Ifyouhelpme,I'llfinishmyjobsoon.→Withyourhelp,I'llfinishmyjobsoon.如果你帮我，我将很快完成我的工作。②Ifthereisnowater,fishcan’tlive.→Fishcan’tlivewithoutwater.离开水，鱼不能生存。（四）if引导的条件状语从句与if引导的宾语从句的区别if引导宾语从句时表示“是否”，位于及物动词之后；if引导的条件状语从句时表示“假如，如果”，位于句首或句中。①Idon'tknowifhewillcometomorrow.②Ifhecomes,I'llcallyou.练习一、选择题1._____youdon'tgotobedearlier,youwillfeeltiredinthemorning.A.UnlessB.IfC.ThoughD.Until2.Whynotlookupthenewwordinadictionary_____youdon'tknowit?A.ifB.thatC.thoughD.whether3.Talktoyourteacherandyouwillgethelp_____youhaveaproblem.A.unlessB.if.C.untilD.so4.Iwon'tgototomorrow'sparty_____I'minvited.A.ifB.unlessC.when5.Thechildrenwillclimbthehillifit_____tomorrow.A.won'trainB.didn'trainC.isn'trainingD.doesn'train6.Wewonderifourteachers_____toourgraduatingpartynextweekend.Ifthey_____,we'llbeveryhappy.A.willcome;willcomeB.come;willcomeC.willcome;comeD.come;come二、翻译句子。1.如果明天下雨，我们将在家看电视。We'llstayathomewatchingTVifit_____（rain）tomorrow.2.如果她早点起床，就有时间在家里吃早餐.Ifshe_____________alittleearlier,she‘llhavetimetoeatbreakfastathome.3.如果你参加聚会，你将会过得很开心。Ifyou______theparty,you____________agreattime.4.如果你经常听英文歌，你将会喜欢英语。Ifyouoften____________Englishsongs,you_____________English.一、BABBDC二、1.rains2.getsup3.join,willhave4.listento,willlike