高中英语语法条件状语从句（20张PPT）.ppt

1、Adverbial clause of condition由引导词if或unless引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后（状语从句中的动作），其它事情（主句中的动作）才能发生，通常译作“假如”。Adverbial clause of condition If you ask him,he will help you.Unless it rains,the game will be played.引导条件状语从句的常用引导词：if,unless,as/so long as,once,in case,on condition that,supposing(that)

2、,providing(that),provided(that),given(that)在条件状语从句中，用一般现在时代替一般将来时，用一般过去时代替过去将来时。语法引导条件状语从句最常用的连词是if，由if引导的条件状语从句表示在某种条件下某事很可能发生。If he runs,hell get there in time.If I have time tomorrow,Ill go to see the film with you.If you look it up in the dictionary,youll find out.如果明天下雪，我们将堆雪人。If it snows tomor

3、row,we will build a snowman.如果你穿上你的衣服，你将不会觉得太冷。If you put on your cloth,you will not feel so cold.unless 引导的条件状语从句 You will fail to arrive there in time unless you start earlier.如果你不早点动身,你就不能及时赶到那儿。Unless it rains,the game will be played.除非下雨,比赛将照常进行。unless从句的谓语只能用肯定式。你若不努力就会失败。You will fail unless

4、you work hard.如果你不快点你又要迟到了。You will be late again unless you hurry.so/as long as只要 You may borrow my book as long as you keep it clean.只要你保持书的清洁，你就可以把我的书借去。只要我还有一口气，我就会努力。Ill work hard as long as I have breath.其它引导词引导的条件状语从句：on condition(that).在条件下，条件是.on condition(that)引导的条件从句是主句事件发生的前提条件或唯一条件。You

5、can use my bike on condition that you return it by Friday.你可以使用我的自行车，条件是你星期五以前还。我会来，条件是也邀请她来。Ill come on condition(that)she is invited tooin case 万一，如果 Take your umbrella in case it rains.带着你的伞吧，以防下雨。万一我忘记，请提醒我一下。In case I forget,please remind me about it.supposing conj.如果,假如supposing引导的条件从句表示一种假设条件

6、。Supposing it rains,shall we continue the sports meeting?倘若下雨,我们的运动会还要继续举行吗?Supposing anything should go wrong,what would you do?假如出了什么问题,你将怎么做?provided/providing conj.假如,除非,以为条件 provided(that)+从句表示一种假设条件。Provided that you promise not to tell anyone,Ill explain the secret 只要你保证不告诉任何人，我就把这个秘密告诉你。Comp

7、lete the sentences with the correct form of the verbs in brackets.1.If you _ a cake your host _ very pleased.(take,be)2.Unless the weather _ better,I _at home.(get,stay)3.He _ home early if he _ well.4.(go,not feel)5.4.What _ I _if they _ about politics?(do,talk)6.5.If you _ your hand the taxi _.(ra

8、ise,stop)7.6.I _ anything unless he _ me.8.(not say,ask)takewill be getswill staywill godoesnt feelshalldotalkraisewill stopwill not sayasksComplete the sentences with whoever,wherever,whenever,or however.1._ I feel lonely,I think about you.2._ he is,he is very rude to me.3._ I go,I always meet inte

9、resting people.4.You can invite _ you like to the party.5._ late you arrive,Ill come and meet you.6.I feel shy _ she says hello to me.7.I hear that song _ I switch on radio.8._ much I study,I find these exercises difficult.Whenever Whoever whereverwhoeverHowever wheneverwheneverHowever 谢谢观赏3.口诀:_条件状

10、语从句：If2.if 从句用_，主句用_，用来描述将来的情况。主将从现1.如果他努力学习，他将会通过考试。2.If he _ hard,he _ the exam.一般将来时一般现在时studieswill pass条件状语从句：If2.if 从句用_，主句也用_，表示客观事实或习惯。3.口诀:_主现从现1.如果我把玻璃杯扔掉，它就会摔碎。2.If I _ a glass,it _.一般现在时一般现在时dropbreaksUnless 如果不，除非nn 条件状语从句:unless 从句遵循if 从句主将从现 和 主现从现 的情况。要领:unless=if not1.如果明天不下雨，我们就去远足

11、。If it _,we will go hiking.=We will go hiking _2.如果你不把肉存放在冰箱里，它就会变坏。If you_ in the fridge,it _.=_in the fridge,it _.Unless=Ifnotunless it rains tomorrow.doesnt rain tomorrowdont keep the meatUnless you keep the meatgoes badgoes badUnless=Ifnot3.除非天下雨，他通常是走路去上学。He usually _ on foot if it _.=_,he usually _ on foot.4.如果你现在不走，你就赶不上火车了。If you _,you _ the train.=_,you _ the train.goes to schooldont leave nowUnless it rainsgoes to schoolUnless you leave nowwont catchwont catchdoesnt rain