条件状语从句PPT课件.ppt

grammar,Conditionalclauses,引导条件状语从句的连接词主要有：if(如果)、unless(除非)或aslongas(只要)等。,条件状语从句,引导条件状语从句最常用的连词是if。如果你请他帮忙,他会帮你的。Ifyouaskhim,hewillhelpyou.如果你考试不及格,你会让他失望的。Ifyoufailintheexam,youwilllethimdown.如果你作业做完了就可以回家了。Ifyouhavefinishedthehomework，youcangohome.,条件状语从句,unless=if.not.除非,若不,除非下雨,比赛将照常进行。Unlessitrains,thegamewillbeplayed.Ifitdoesntrain,thegamewillbeplayed.让我们出去散步吧，除非你太累了。Letsgooutforawalkunlessyouaretootired.Ifyouarenottootired,letsgooutforawalk.,条件状语从句,1.除非你早点动身，你就不能及时赶到那儿。YouwillfailtoarrivethereintimeunlessyoustartearlierYouwillfailtoarrivethereintimeifyoudontstartearlier2.除非天气不好，我每天早晨都要去慢跑。Unlessbadweatherstopsme，IgojoggingeverymorningIfbadweatherdoesntstopme，Igojoggingeverymorning3.除非你需要，我不会借钱给你的。IwontlendyoumoneyunlessyouareinneedIwontlendyoumoneyifyouarenotinneed,3、so/aslongas只要只要你保持书的清洁，你就可以把我的书借去。Youmayborrowmybookas/solongasyoukeepitclean.只要你高兴，你做什么都没有关系。So/Aslongasyourehappy,itdoesntmatterwhatyoudo.只要你努力，你就会成功。Youllsucceedas(so)longasyoutryhard.,条件状语从句,时态问题在条件状语从句中，要注意主将从现的规定，即主句用一般将来时，从句用一般现在时表示将来时。我有时间，我就来看你。IwillcometoseeyouifIhavetime.,条件状语从句,If从句（一般现在时），主句（一般现在时）,表示科学常识，经常性的动作1.如果水被加热，它会变成蒸汽。Ifwaterisheated,itturnstosteam.2.如果我需要理发，我通常去我家附近的理发店。IfIneedahaircut,IusuallygotothebarbersnearwhereIlive.3.如果天下雨，人们通常星期天不出门。PeopleoftendontgooutonSundaysifitrains.,表示将来的可能性时，运用“主将从现”的原则。,1.如果我得到这项工作，我将会买个手机。IfIgetthejob,Illbuyamobilephone.如果我的家庭作业很难，我会叫Helen帮助我。2.Ifmyhomeworkisdifficult,IllaskHelentohelpme.如果我今天下午有时间，我将去和同学踢足球。3.IfIhavetimethisafternoon,Illgotoplaysoccerwithmyclassmates.,典型例题：Ifhe_inhalfanhour,we_waitforhim.A.wontcome,wontB.wontcome,dontC.doesntcome,wontD.willcome,dont,条件状语从句,误区提醒if既可以引导条件状语从句，表示如果，也可以引导宾语从句，表达是否。辨别它在这两种从句中的时态是我们经常容易出错的地方。另外，if和unless的用法也需注意,条件状语从句,1.Ifit_tomorrow,we_toclimbmountains.A.doesntrain;goB.wontrain;willgoC.wontrain;goD.doesntrain;willgo2Doyouknowif_tomorrowmorning?No.Iwillcallyouifshe_back.A.shewillcome;comesB.shecomes;willcomeC.willshecome;comesD.willshecome;willcome,条件状语从句,3Wellgototheparkifit_raintomorrow.A.dontB.doesntC.wont4Wearenotsureifit_tomorrow.Ifit_,oursportsmeetingwillbeputoff.A.rains;rainsB.rains;willrainC.willrain;willrainD.willrain;rains,条件状语从句,5.Illgivethebooktohimaslongashe_herenextSunday.A.willcomeB.comesC.iscomingD.came6.Youwillnotgetgoodgrades_youworkhard.A.andB.unlessC.ifD.aslongas,条件状语从句,40.WillyoupleasegivethedictionarytoJane?Sure,Illgiveittoher_shearriveshere.A.beforeB.untilC.becauseD.assoonas,37.Asnakebithim_hewenttoseeadoctoratonce.A.ifB.whereC.becauseD.so,28.Youwillbelateforschool_youdontgetupearly.A.butB.ifC.andD.or,34.Itwasrainingheavily,_wede