条件状语从句ppt课件.ppt

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1、grammar,Conditional clauses,引导条件状语从句的连接词主要有：if(如果)、unless(除非)或 as long as(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。If you ask him,he will help you.如果你考试不及格,你会让他失望的。If you fail in the exam,you will let him down.如果你作业做完了就可以回家了。If you have finished the homework，you can go home.,条件状语从句,unless=if.not

2、.除非,若不,除非下雨,比赛将照常进行。Unless it rains,the game will be played.If it doesnt rain,the game will be played.让我们出去散步吧，除非你太累了。Lets go out for a walk unless you are too tired.If you are not too tired,lets go out for a walk.,条件状语从句,1.除非你早点动身，你就不能及时赶到那儿。You will fail to arrive there in time unless you start ea

3、rlierYou will fail to arrive there in time if you dont start earlier2.除非天气不好，我每天早晨都要去慢跑。Unless bad weather stops me，I go jogging every morningIf bad weather doesnt stop me，I go jogging every morning3.除非你需要，我不会借钱给你的。I wont lend you money unless you are in need I wont lend you money if you are not in

4、need,3、so/as long as只要只要你保持书的清 洁，你就可以把我的书借去。You may borrow my book as/so long as you keep it clean.只要你高兴，你做什么都没有关系。So/As long as youre happy,it doesnt matter what you do.只要你努力，你就会成功。Youll succeed as(so)long as you try hard.,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。I will com

5、e to see you if I have time.,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。If water is heated,it turns to steam.2.如果我需要理发，我通常去我家附近的理发店。If I need a haircut,I usually go to the barbers near where I live.3.如果天下雨，人们通常星期天不出门。People often dont go out on Sundays if it rains.,表示将来的可能性时，运用“主将从现”

6、的原则。,1.如果我得到这项工作，我将会买个手机。If I get the job,Ill buy a mobile phone.如果我的家庭作业很难，我会叫Helen帮助我。2.If my homework is difficult,Ill ask Helen to help me.如果我今天下午有时间，我将去和同学踢足球。3.If I have time this afternoon,Ill go to play soccer with my classmates.,典型例题：If he _in half an hour,we _wait for him.A.wont come,wont

7、B.wont come,dontC.doesnt come,wontD.will come,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;go D.doesntrain;willgo2Doyouknowif_tomorrowmorning?No.Iwillcallyouifs

8、he_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;rains B.rains;willrainC.willrain;willrainD.willrain;rains,条件状语从句,5.Illgivethebook

9、tohimaslongashe_herenextSunday.A.willcomeB.comesC.iscomingD.came6.Youwillnotgetgoodgrades _ youworkhard.A.andB.unlessC.ifD.aslongas,条件状语从句,40.Will you please give the dictionary to Jane?Sure,Ill give it to her _ she arrives here.A.beforeB.until C.becauseD.as soon as,37.A snake bit him _ he went to s

10、ee a doctor at once.A.if B.where C.because D.so,28.Youwillbelateforschool_youdontgetupearly.A.but B.if C.andD.or,34.It was raining heavily,_ we decided to stay at home and watch TV.A.unless B.if C.because D.so,36._ the dinner was all over,everyone helped wash the dishes.A.as long as B.When C.Before D.if,