条件状语从句.docx

1、条件状语从句条件状语从句条件状语从句的定义 在句子中做条件状语的从句称为条件状语从句。可置于句首、句尾，有时还可置于主语和谓语之间。引导条件状语从句的连接词有：if ,unless,as/so long as等条件状语从句的引导词 1.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 we pay much attention to the earth, well have a better world. 如果我们多关爱地球，就会拥有一个更美好的世界 If it rains tomorrow, what shall we do? 如果明天下雨，我们怎么办？ 注意：if还可以引导虚

2、拟条件句，表示不可实现的条件，从句中多用一般过去时或过去完成时。What would happen if there were no water ?如果没有水会怎样？2.unless引导的条件状语从句unless的意思是如果不，除非。可与if.not互换。You will fail in English unless you work hard.你英语考试会不及格的，除非你更加努力。3.as /so long as引导的条件状语从句 as /so long as意思是“只要”So long as youre happy,i will be happy.只要你高兴，我就高兴。4.once引导的条

3、件状语从句once引导的条件状语从句，意为“一旦.，就”，从句可置于主句前或后Once you begin,never stop.一旦开始，就绝不要停止Maths is easy to learn once you understand the rules.一旦你理解了规则，数学就不难学了。条件状语从句的种类条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条件句表示的是假设或实际可能性不大的情况，故采用虚拟语气。 eg.If he doesnt hurry up,he will miss the bus.如果他不快点，他将错过巴士。( 真实) If he is free,he w

4、ill ask me to tell stories.如果他是空闲的，他会要求我讲故事。（真实） If I were you,I would go at once.如果我是你，我马上就会去。（我不可能是你。非真实，虚拟语气） If there were no air,people would die.如果没有空气，人就会死亡。（不可能没有空气。非真实，虚拟语气） 用法及动词形式1、表示与现在事实相反的情况： 从句：If 主语+过去时(Be动词用were) 主句：主语+should/would/could/might+do eg： 1If I were you,I would take an u

5、mbrella. 如果我是你，我会带把伞。（事实：我不可能是你） 2If I knew his telephone number,I would tell you. 如果我知道他的电话号码，我就会告诉你。（事实：不知道） 3If there were no air or water,there would be no living things on the earth. 如果没有水和空气，地球上就不会有生物。(事实：地球上既有空气也有水) 4If I had any money with me,I could lend you some. 如果我带钱了，我就会借给你些。（事实：没有带钱） 2

6、、表示与过去事实相反的情况 从句：If 主语+had+done 主句：主语+should/would/could/might+have done eg： 1 If I had got there earlier,I should/could have met her. 如果我早到那儿，我就会见到她。 （事实：去晚了） 2If he had taken my advice,he would not have made such a mistake. 如果他听我的劝告的话，就不会犯这样的错误了。 （事实：没有听我的话） 3、表示对将来情况的主观推测 从句：if+主语+were to do 主句：主

7、语+should/would/could/might+do if+主语+did/were 主语+should/would/could/might+do if+主语+should+do 主语+should/would/could/might+do eg： 1If he should come here tomorrow,I would talk to him. 如果他明天来这儿的话，我就跟他谈谈。（事实：来的可能性很小） 2If there were a heavy snow next Sunday,we would not go skating. 如果下周日下大雪，我们就不能去滑冰了。（事实：

8、下雪可能性很小） 3If she were to be here next Monday,I would tell her about the matter. 如果她下周一来这儿的话，我就会告诉她这件事的始末。（事实：来的可能性很小） 4、 有时，虚拟条件句中，结果主句和条件从句的谓语动作若不是同时发生时，虚拟语气的形式应作相应的调整。这种条件句叫错综条件句。 从句的动作与过去事实相反，而主句的动作与现在或现在正在发生的事实不符。 eg： If I had worked hard at school,I would be an engineer,too. 如果我在学校学习刻苦的话，我现在也会成

9、为一个工程师了 If they had informed us,we would not come here now. 如果他们通知过我们的话，我们现在就不会来这里了。 从句的动作与现在事实相反，而主句的动作与过去事实不符。 如： If he were free today,we would have sent him to Beijing. 如果他今天有空的话，我们会已经派他去北京了。 If he knew her,he would have greeted her. 要是他认识她的话，他肯定会去问候她了。 5、 当虚拟条件句的谓语动词含有were,should,had时，if可以省略，这时

10、条件从句要用倒装语序，即把were,should,had等词置于句首，这种多用于书面语。eg： Should he agree to go there,we would send him there. 要是他答应去的话，我们就派他去。 Were she here,she would agree with us. 如果她在这儿的话，她会同意我们的。 Had he learnt about computers,we would have hired him to work here. 如果他懂一些电脑知识的话，我们已经聘用他来这里工作了。 6、非真实条件句中的条件从句有时不表达出来，只暗含在副词、

11、介词短语、上下文或其他方式表示出来，这种句子叫做含蓄条件句，在多数情况下，条件会暗含在短语中，如without，but for等 eg： But for his help,we would be working now. 要不是他的帮助，我们还会在工作呢。 Without your instruction,I would not have made such great progress. 要是没有你的指导，我不会取得如此大的进步。 We didnt know his telephone number,otherwise we would have telephoned him. 我们不知道他

12、的电话号码，否则我们就会给他打电话。 7、 有时，虚拟条件句中，主、从句可以省略其中的一个，来表示说话人的一种强烈的感情。 省略从句 He would have finished it. 他本该完成了。 You could have passed this exam. 你本能通过这次考试的。 省略主句 If I were at home now. 要是我现在在家里该多好啊。 If only I had got it. 要是只有我得到它了该多好啊。 8.注意，在虚拟语气的从句中，动词be的过去时态一律用were，不用was。 eg：If I were you,I would go to look

13、 for him. 如果我是你，就会去找他。 条件状语从句的时态原则条件句从句主句真实一般现在时一般将来时情态动词+动原祈使句非真实一般过去时be动词用（were）would/could+动原在条件状语从句中，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。If the weather is bad next week, well put off the climbing.如果下周天气不好，我们将推迟爬山。Father told me if I worked hard he would buy me a gift.爸爸告诉我，如果我努力学习，他会给我买一份礼物。注意 ：学习 if 引导

14、的条件状语从句的用法,现在总结一下: if 条件句不一般,几个要点记心间; 条件句,放在前,逗号要放句中间。 条件句表可能，主句多用将来时； 条件句表事实，主句常用现在时。在 if 引导的条件状语从句中，如果从句谈论的是一个有可能发生的事实及其产生的相关的结果，主句用一般将来时态，从句用一般现在时态。如： We can walk there if we cant find a bus . If it rains tomorrow ,we will not go to the zoo. What will you do if you find a panda in danger.如果 if 条件

15、句谈论的是重复发生和预示要发生的情景和事件，则主从句大多用一般现在时态。如： If bears are in danger ,they attack people.在 if 引导的条件状语从句中，if 和条件句位置灵活，可直接放在主句后面，若 if 条件句放句首， 从句后面要加逗号，和主句隔开。还要注意前后时态一致原则条件状语从句中考题1.【2011北京】 I will send you an e-mail as soon as I_ in Canada.A. arrive B. arrived C. am arriving D. will arrive答案：A【解析】考查点：本题考查状语从句

16、的时态的用法。当主句是将来时态时，状语从句用一般时态来代替将来时，所以选择答案A。2.【2011陕西】 If there no buying and selling of animals, there no killing in nature.A. is; will he B. will be; will be C. is; is D. will be; is答案：A 【解析】考查点：本题考查if引导的状语从句的时态。if 意为“如果”。引导条件状语从句，主将从现。故选A。3.【2011黑龙江绥化市】 Im waiting for my friend._, Ill go shopping al

17、one.A. If she comes B. If she wont come C. If she doesnt come答案：C【解析】考查从句的时态。If引导的条件状语从句，主句用将来时，从句用一般现在时。根据句意：如果他不来，我就独自去购物。故选C。4.【2011黑龙江绥化市】 Mr. Green speaks very loudly _all the people can hear him clearly.A. when B. so that C. because 答案： B【解析】词义辨析。When 是“当-的时候”的意思；so that是“为了，目的是”的意思；because是“因

18、为”的意思；本句中，so that 引导的目的状语从句。5.【2011内蒙古包头】 You cant watch TV _ you finish your homework.A. before B. if C. while D. as答案：A【解析】本题考查词义辨析。A项意为“在之前”；B项意为“假如；即使”；C项意为“当时候”；D项意为“因为”。句意为“你不能看电视在你完成作业_”。根据语可知此空应为before.故选A。6.【2011哈尔滨】 As we all know, planting trees is good for the environment. Our class will

19、 go to the Sun Island tomorrow. As soon as we there, well begin to plant trees.A. arrived B. arrive C. will arrive答案：B【解析】考查状语从句的时态。在as soon as引导的时间状语从句中，如果主句和从句的动作都发生在将来，从句用一般现在时表示将来，句意：我们一到那儿，我们就开始植树。故选B.7.【2011雅安】 The students _ have a sports meeting this weekend if it _.A. wont; rains B. will; r

20、ainsC. wont; will rain D. are going to; is going to rain答案：A【解析】考查if引导的条件状语从句用法。if意为“如果”，引导条件状语从句，主句用一般将来时，从句用一般现在时态。句意为“如果明天下雨我们就不举行运动会了”。故选A。8.【2011湖南湘西】 Dont talk loudly at the meeting. If you _, you will have to leave.A. doB. are C. did答案：A【解析】考查状语从句的时态当主句为将来时态是，if引导的状语从句中用一般时态代替将来时，而这里需要助动词，不是系

21、动词，所以选择答案A。9.【2011湖南益阳】 I dont know if she to my birthday party tomorrow. If she , Ill be very happy.A. comes; comes B. will come; comes C. comes; will come答案：B【解析】宾语从句和条件状语从句的考查。由if引导的条件状语从句，用一般现在时态，主句用一般将来时。当if做是否讲时，所引导的宾语从句通常是一般将来时。10.【 2011大庆】 When will you come to Daqing? I will call you _I arr

22、ive.A. tillB. while C. as quickly as D. as soon as 答案：D11.【2011广西崇左】 Ill give it to Jim as soon as I _him tomorrow.A. saw B. will see C. see D. have seen【解析】C 考查点：考察条件从句的时态。解题思路：as soon as表示“一就”，其主句用将来时态，从句要用一般现在时态。故选C。12.【2011黑龙江齐齐哈尔】 Im waiting for my friend. , Ill go shopping alone.A. If she come

23、s B. If she doesnt come C. If she wont come答案：B13.【2011重庆江津】 If she here tomorrow, I will tell you.A. comesB. will come C. come D. came答案：A14.【2011山东滨州】 Mary, could you tell me if your mother _our school sports meeting tomorrow?I think she will come to school if she _ free.A. will take part in; will

24、 be B. takes part in; is C. will take part in; is D. takes part in; will be答案：C【解析】考查if引导的宾语从句及条件状语从句的用法。问句是由if引导的宾语从句，时间状语为 tomorrow，故用一般将来时；答语是由if引导的条件状语从句，主句用将来时，从句用一般现在时，故选C。15【2011山东泰安】 Tom wants to know if you will have a picnic tomorrow.Yes. But if it _, well play chess instead.A. will rain B

25、. rained C. is raining D. rains答案：D【解析】连词的用法。If引导的条件状语从句，主句用将来时，从句用一般现在时。故选D。16【2011福州中考】 You study _ hard _ youre sure to pass the exam. Thank you for saying so. A. enough to B. asas C. sothat答案：C 【解析】考查sothat的用法。enough.to“足够做”；as.as.“和一样”；so.that.“如此以至”。由句意：你学习如此的努力以至于你肯定能通过考试。谢谢你这么说。故选C。17.【2011山

26、东潍坊】 If Tom _ the game, well give him a surprise.A. win B. wins C. wonD. miming答案：B【解析】考查if引导的条件状语从句。在if引导的条件状语从句中，如果主句和从句发生的动作都在将来时间，从句用一般现在时表将来。故选B。18.【2011浙江宁波】 I hear the famous singer Xu Song may come to Ningbo next month. Really? _ he comes, my younger sister will be very excited.A. If B. Unti

27、l C. Unless D. Before答案：A 【解析】状语从句考查。if如果；until到为止；unless除非；before在之前。根据句意，如果他来，我的妹妹将会很激动的。【2011广安市】38. What time will Diana get to Chengdu?Im not sure. When he _, Ill call you. A. will arrive B. arrive C. arrives 答案：C【解析】考查从句的时态。When引导的时间状语从句中，如果主句和从句的动作都发生在将来，主句用将来时，从句用一般现在时。he是单数第三人称形式，故用arrives。

28、19.【2011山东临沂】 Zhou Libo is Shanghais favorite funny man. He is good at making people laugh. His lively shows were _ hot that tickets sold out in minutes. A. very B. too C. such D. so 答案：D 【解析】句型考查。句中的句型为sothat, 意为“如此.以至于”，so 用来修饰形容词或副词，such也构成这一句型，但such 用来修饰名词。【2011山东德州】19. They develop their skills _ they can do things better and better.A. however B. because C. since D. so that答案：D【解析】状语从句。句意：他们拓展他们的技能是为了他们能够把事情做的越来越好。后面的从句表示目的，只有D符合题意。20.【2011山东德州】 They develop their skills _ they can do things better and better.A. however B. because C. since D. so that答案：D【解析】考