初中英语语法——If引导的条件状语从句(讲解及练习)

if引导的条件状语从句引导条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。

如：If you ask him，he will help you．如果你请他帮忙，他会帮你的。

If you fail in the exam，you will let him down．如果你考试不及格，你会让他失望的。

If you have finished the homework，you can go home．如果你作业做完了就可以回家了。

另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。

从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。

如：If I were you，I would invite him to the party．如果我是你，我会邀请他参加聚会。

I would have arrived much earlier if I had not been caught in the traffic．要不是交通堵塞，我本会来得早一些。

另外你还要注意if 条件句的时态搭配1．if从句用一般现在时，主句用一般将来时If he runs he’ll get there in time. 如果他用跑的，他就会及时赶到那儿。

The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。

2．if从句用一般现在时，主句用may/might/canIf the fog gets thicker the plane may/might be diverted. 如果雾在大一些，飞机可能就会改在别的机场降落。

If it stops snowing we can go out. 如果雪停了，我们就可以出去。

3．if从句用一般现在时，主句用must/shouldIf you want to lose weight you must/should eat less bread. 如果你想减肥，你必须少吃面包。

I（一）f引导条件状语从句的详细用法解答引导条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。

如：If you ask him，he will help you．如果你请他帮忙，他会帮你的。

If you fail in the exam，you will let him down．如果你考试不及格，你会让他失望的。

If you have finished the homework， you can go home．如果你作业做完了就可以回家了。

另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。

从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。

如：If I were you，I would invite him to the party．如果我是你，我会邀请他参加聚会。

I would have arrived much earlier if I had not been caught in the traffic．要不是交通堵塞，我本会来得早一些。

另外你还要注意if 条件句的时态搭配1．if从句用一般现在时，主句用一般将来时If he runs he’ll get there in time. 如果他用跑的，他就会及时赶到那儿。

The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。

2．if从句用一般现在时，主句用may/might/canIf the fog gets thicker the plane may/might be diverted. 如果雾在大一些，飞机可能就会改在别的机场降落。

If it stops snowing we can go out. 如果雪停了，我们就可以出去。

3．if从句用一般现在时，主句用must/shouldIf you want to lose weight you must/should eat less bread. 如果你想减肥，你必须少吃面包。

初中英―― if 引的条件状从句在 if 引的条件状从句中， if 和条件句地点灵巧，可直接放在主句后边，若 if 条件句放句首，从句后边要加逗号，和主句分开。

要注意前后一致原 .引条件状从句的接主要有： if( 假如）、unless（除非）或 as long as（只需）等。

unless在乎思上等于 if...not。

一、条件状从句用法1、引条件状从句最常用的是if, 由 if 引的条件状从句表示在某种条件下某事很可能生。

如：If you ask him, he will help you.假如你他帮忙 ,他会帮你的。

If you fail in the exam, you will let him down.假如你考不及格 ,你会他绝望的。

此外 ,if 从句表示不行的条件或根本不行能存在的条件 ,也就是一种虚的条件或假 ,从句多用一般去或去达成。

如 :If I were you, I would invite him to the party.假如我是你 ,我会邀他参加聚会。

2、 unless = if...not. 除非 ,若不 ,除非在⋯⋯的候比如：Let's go out for a walk unless you are too tired.=If you are not too tired, let's go out for a walk.Unless it rains, the game will be played.除非下雨 ,比将照旧行。

二、在条件状从句中，要注意“主将从”的定，即主句用一般未来，从句用一般在表示未来。

例句：I will come to see you if I have time.我有，我就来看你。

三假如 if 条件句的是重复生和示要生的情形和事件，主从句大多用一般在。

如：If bears are in danger ,they attack people.区提示if 既能够引条件状从句，表示“假如”，也能够引从句，表达“是否”。

语法专题：条件状语从句（1）if条件句：有可能性结果发生的行动，在这些句子中，动词的时态是不同的，if 引导的条件状语从句中，主句用一般将来时态，从句用一般现在时态（主将从现）If it doesn’t rain（从句）, we’ll have a picnic tomorrow（主句）.We’ll have a picnic tomorrow, if it doesn’t rain.（if引导的从句可置前可置后）（2）主祈从现（祈使句+if+一般现在时态）Put up your hands if you have any questions to ask. 如果你们有问题问的话，请举手。

当主语是you时，if 引导的条件状语从句可以与”祈使句+and/ or +简单句”进行句型转换。

And 表示句意顺承，or 表示转折，意为”否则”。

Take care , or you will fall off the tree. = If you don’t take care, you’ll fall off the tree. 小心，否则你会从树上掉下来。

（3）主情从现（情态动词+if +一般现在时态）If I get there early, I can see the doctor quickly.（4）句型：will do式be going to do式肯定从句If主语+动词+其他, 主语+will(won’t) do+其他. If主语+动词+其他, 主语+be(be not) going to do+其他.否定从句If主语+be+not+其他, 主语+will(won’t) do+其他. If主语+be+not+其他, 主语+be(be not) going to do+其他.If主语+don't/ doesn't +动词原形+其他, 主语+will(won’t) do+其他. If主语+don't/ doesn't +动词原形+其他, 主语+be(be not) going to do+其他.If the picture is silly, strange and colourful, you will remember it better.If I have time, I am going to visite you .I will go to the park if it doesn’t rain tomorrow . I won't go to the park if it rains tomorrow.专题精讲实战演练题型1：单项选择( ) 1. If the robot ___________ wrong，you can get a new one for free or get all your money back.A. wentB. goesC. would goD. will go ( ) 2. —We’ll go for a picnic if it ___________ on Sunday.—Wish you a lovely weekend.A. rainB. doesn’t rainC. won’t rainD. rains ( ) 3. I’ll do it better if the teacher ___________ me another chance.A. giveB. givesC. gaveD. will give( ) 4. If a polar bear ___________, it ___________ fish from the waterA. will be hungry；catchesB. is hungry；will catchB. is going to be hungry；catches D. is hungry；won’t catch( ) 5. If our government ___________ attention to controlling food safety now, our health ___________ in danger.A. won’t pay; isB. doesn’t pay; isC. won’t pay; will beD. doesn’t pay; will be( ) 6. We will go for a picnic if it___________ tomorrow.A. doesn’t rainB. wasn’t rainyC. won’t rainD. wasn’t raining( ) 7. If the pure water is heated to 100 centigrade degrees, it___________ boil.A. is going toB. willC. wouldD. is to ( ) 8. She will go to America___________ she has much free time and money.A. as long asB. butC. thoughD. although( ) 9. We will go to the West Lake___________ it doesn’t rain heavily tomorrow.A. ifB. unlessC. as long asD. once ( ) 10. I won’t call you, ___________ something unexpected happens.A. unlessB. whetherC. becauseD. While Keys: 1-5 BBBBD 6-10ABAAA题型2：以所给词的正确形式填空1. If he ________ (study) hard, he will get good grades.2. Everyone must wear uniforms. If you don't, they ___________ (let) you in.3. If you stand at the top of the mountain, you _________ (see) the view of the whole city.4. My grandfather will wear a pair of glasses if he__________ (read) newspapers.5. Please turn off the light if you ________ (leave) the classroom.6. We’ll go for a picnic unless it ________(rain) this Sunday.7. Mr Smith ________ (let) you know if he needs help.8. If you walk along the street, you ________ (see) many foreigners.9. If Mary ________ (ask) me for help，I will try my best to help her.10. I don't know if it will snow tomorrow. If it_______ (snow)，we'll make snowmen. Keys:1. Studies 2.won’t let 3. will see 4. reads 5.leave6.doesn’t rain7.will let8.will see9. asks 10.snows直击中考题型1：单项选择( ) 1.—I wonder if your wife ________ to the party.—If your wife _________, so will mine.A. will go, goB. will go, goesC. goes, will goD. will go, will go ( ) 2. If he _________ in half an hour, we _________ wait for him.A. won't come, won'tB. won't come, don'tC. doesn't come, won'tD. will come, don't ( ) 3. I will send you an e-mail as soon as I_________ in Canada.A. arriveB. arrivedC. am arrivingD. will arrive( ) 4. If there ________ no buying and selling of animals, there _________ no killing in nature.A. is; will beB. will be; will beC. is; isD. will be; is ( ) 5. You can’t watch TV ________ you finish your homework.A. beforeB. ifC. whileD. asKeys:1-5:ACAAA。

初二英语状语从句中if引导的条件状语从句解析【考纲解读】1.掌握各种条件状语从句，如本文中的if引导的条件状语从句。

2. 正确使用各种状语及其时态。

3. 掌握条件状语中“主将从现”的用法。

【知识点梳理】引导条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。

如：If you ask him，he will help you.如果你请他帮忙，他会帮你的。

If you fail in the exam，you will let him down.如果你考试不及格，你会让他失望的。

If you have finished the homework， you can go home.如果你作业做完了就可以回家了。

另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。

从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。

如：If I were you，I would invite him to the party.如果我是你，我会邀请他参加聚会。

I would have arrived much earlier if I had not been caught in the traffic.要不是交通堵塞，我本会来得早一些。

另外你还要注意if 条件句的时态搭配1.if从句用一般现在时，主句用一般将来时If he runs he’ll get there in time. 如果他用跑的，他就会及时赶到那儿。

The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。

2.if从句用一般现在时，主句用may/might/canIf the fog gets thicker the plane may/might be diverted. 如果雾在大一些，飞机可能就会改在别的机场降落。

if引导的条件状语从句（讲义及解析）状语用来表示行为发生的时刻、地点、目的、方式、程度等，通常由副词或介词短语充当，也可由一个句子充当。

I slept at home yesterday because I had a bad cold.状语从句状语从句指句子作状语。

依照其作用可分为时刻、地点、缘故、条件、目的、结果、让步、方式等从句。

状语从句一样由连词(从属连词)引导。

I will go to school by bike tomorrow if it is sunny.Grammar focus—I think I’ll take the bus to the party.—If you do, you’ll be late.If you take the bus to the party, you’ll be late.—I think I’ll stay at home.—If you do, you’ll be sorry.If you stay at home, you’ll be sorry.—What will happen if they have the party today?—If they have it today, half the class won’t come.—Should we ask people to bring food?—If we ask people to bring food, they’ll just bring potato chips and chocol ate.if 在本单元句中意为“；”，用于引导即 if 引导的是一个完整的句子，因此一定要有主谓，成为从句，另一个句子则成为主句。

If you go there, I’ll go, too.We will go hiking if it doesn’t rain tomorrow.If Bob leaves tomorrow, I will hold a party for him tonight.if 引导的条件状语从句既能够放在主句前，也可放在主句后。

If引导的条件状语从句的讲解与练习一、if从句的位置if引导的从句可以放在主句之前，也可以放在主句之后。

Eg: If you do not feel well, go to see the doctor.Go to see the doctor if you do not feel well.二、if从句的类型：1.if从句+祈使句(表建议: 如果......就......)主祈从现Eg: If you want to go to the cinema, call me.2.if从句，主语+will(not) +V.(动词原形)主将从现Eg: If you start now, you'll finish it before dinner.If it is sunny tomorrow, we will go for a picnic.3.if从句，主语+may(might)/could+V.(动词原形)主情从现Eg: If you work hard, you might not make so many mistakes.即学即练一、单项选择。

1.If you _____ to the party, you’ll have a great timeA. will goB. wentC. go2. I ____ her the answer if she ____me.A. can tell, will askB. will tell, will askC. would tell, askD. will tell, asks3 – What are you going to do tomorrow? —We’ll go to the library tomorrowif it ___.A.isn’t rainB. rainC. won’t rainD. doesn’t rain4. What will you do if you _____ to the old folk’s home visit?A. goB. went D. will go5. If I eat ____ food, I’ll be very fat.A. too manyB. many tooC. too muchD. much too6. I’ll give the book to him if he ___ here next Sunday.A. will eB. esC. is ingD. Came7. Our world will get better and better each of us lives a greener life.A. beforeB. ifC. thoughD. until8. If he ________hard, he will get good gradesA. studyB. studiesC. will studyD. studied9. I want to know if Mary________ to the party tomorrow.A. goB. wentC. will goD. goes10. Everyone must dress up. If you_______ ,they won’t let you in.A. don’tB. won’tC. can’tD. mus tn’t11. Johnson won't answer the phone if he _______ the number.A. knewB. doesn't knowC. will knowD. didn’t know12. If Nancy_____the exam, she will go to Australia for English study.A. passB. passedC. passesD.will pass13. There will be less pollution more people use publictransportation.A.butB.thoughC.unlessD. if二、用所给词的适当形式填空。

千里之行，始于足下。

202X年中考英语语法专题讲解之If条件从句总结及练习If条件从句是英语语法中一个格外重要的语法结构，用于表示假设、条件或可能性。

在中考英语考试中，经常会涉及到If条件从句的使用。

下面是一个关于If条件从句的总结及练习。

一、If条件从句的基本结构If条件从句通常由if引导，后接一个简洁句。

基本结构如下：If + 简洁句，主句。

二、使用时留意的几个要点1. If条件从句表示的是假设、条件或可能性，主句表示的是依据这个假设、条件或可能性，所产生的结果。

2. 假如If条件从句是现在时态，主句可以是将来时态。

例：If it rains, I will stay at home.假如下雨的话，我就会呆在家里。

3. 假如If条件从句是过去时态，主句可以是过去将来时态。

例：If I had enough money, I would buy a new car.假如我有足够的钱的话，我就会买一辆新车。

4. 假如If条件从句是过去完成时态，主句可以是过去完成时态。

例：If I had known the answer, I would have told you.假如我知道答案的话，我就会告知你。

5. 在If条件从句中，时态要依据实际状况来选择，不能任凭变换。

6. 假如If条件从句中的动作是客观真理、律师、科学事实等，主句可以使用一般现在时。

例：If you heat ice, it melts.假如你加热冰的话，它会溶化。

第1页/共3页锲而不舍，金石可镂。

三、If条件从句的练习题1. ________ it rains tomorrow, we won't go for a picnic.A. IfB. WhetherC. ThoughD. Unless2. What will you do if you ________ the match?A. will loseB. would loseC. lostD. lose3. If I ________ free tomorrow, I will go to see a movie.A. amB. will beC. would beD. were4. ________ you work hard, you won't pass the exam.A. IfB. UnlessC. As soon asD. Because5. If it ________ tomorrow, we will have a picnic.A. will rainB. would rainC. rains千里之行，始于足下。

if用法详解(含练习和答案)If的用法一、if作为连词，引导条件状语从句，表示“假如”“如果”等。

在复合句中，如果主句使用将来时，则if引导的状语从句使用一般现在时。

例如：1.如果天不下雨，下周星期天我们将去公园。

2.如果你请求他，他将会帮助你。

二、if还可以引导让步状语从句。

这时if相当于“即使是”，“虽说”。

例如：1.虽然她很穷，但至少她还是诚实的。

2.即使我错了，那么你也不对。

3.虽然会花费我一下午的时间，我还是要做这件事。

三、if作为连词还可以引导宾语从句。

引导宾语从句时和whether意思相同。

例如：1.XXX问她是否喜欢它。

2.她问他们是否有一件棉织的。

四、用于虚拟语气中，if从句中使用过去式，表示不可能实现、大概不会实现或提出作为考虑的假定条件。

例如：1.假使你是只鸟，你便会飞了。

2.如果我向他借贷，他会答应吗？另外，if从句中使用过去完成式，表示过去未实现的条件（例如由于不可能实现或某人未能实行）。

例如：1.要是他们早些动身，他们便可及时到达了。

2.如果他们那时不动身，现在他们就不会在此地了。

人一样。

2.As if by magic，the XXX.)花儿一夜之间就像魔法一样开了。

其次，unless与if连用，表示“除非”的意思。

例如：1.Unless you work hard，you won’t succeed．(If you don’t work hard。

you won’t succeed.)除非你努力工作，否则你不会成功。

2.I won’t go unless you come with me．(If you don’t com e with me。

I won’t go.)除非你和我一起去，否则我不会去。

最后，suppose与if连用，表示“假设、设想”的意思。

例如：1.Suppose it rains tomorrow，what will you do。

(If it rains tomorrow。

初中英语――条件状语从句（讲解&练习）Ⅰ条件状语从句的定义Ⅱ条件状语从句的引导词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, we'll 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。

:/so long as引导的条件状语从句as /so long as意思是“只要”So long as you're happy,i will be happy.只要你高兴，我就高兴。

Ⅲ条Array件状语从句的种类Ⅳ条件状语从句的时态原则注意：学习" if " 引导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。

\条件句表真实，主将从现要遵从；条件句非真实，虚拟语气用到位。

练习Ⅰ.单项选择（）you _____ to the party, you’ll have a great time.A. will goB. wentC. goD. going（）2. I ____ her the answer if she ____me.A. can tell, will askB. will tell, will ask…C. would tell, askD. will tell, asks（）3. – What are you going to do tomorrow--We’ll go to the library tomorrow if it ___.A. isn’t rainB. rainC. won’t rainD. doesn’t rain（）4. What will you do if you _____ to the old folk’s homeA. goB. wentC. goingD. will go（）5．I’ll give the book to him if he ___ here next Sunday.A. will comeB. comesC. is comingD. came《Ⅱ.用所给词的适当形式填空6..If you ________(feel) tired, you _______________ (have) to have a rest.7. Where _______ he _________(see) the film if he ________________(have) time8. If there __________(be) fewer trees, there _______________( be) more pollution.9. If Marcia _____________(live) alone, she ___________________( keep) a pet parrot.11. Lana ________________( buy) a new dress if the old one ____________(be) out of style.twins ______________(fight) if they_______________(argue).13. I ____________(have) a bake sale if I _____________(need) money for education.|14. Peter _____________( send) me a beautiful souvenir if he ________________(tour) Spain.15. I ____________(go) to the beach if it________________ ( not rain) this week.17. __________they __________( have) a match if the . teacher _____________(be) busy18. If she ____________(get) up late, she _____________ ( not catch) the early bus.Ⅲ.翻译下列句子19..如果他到的晚了会发生什么事情What _______________ if he _____________ late20. 如果努力学习，你就会取得好成绩。

八年级英语‎：i f引导的‎条件状语从‎句常见的if‎条件状语从‎句表示在某‎条件下，某事很可能‎发生，条件是可能‎存在的，主句中某种‎情况发生的‎概率也是很‎高的。

如：If you ask him，he will help you．如果你请他‎帮忙，他会帮你的‎。

If you fail in the exam，you will let him down．如果你考试‎不及格，你会让他失‎望的。

If you have finis‎h ed the homew‎o rk，you can go home．如果你作业‎做完了就可‎以回家了。

另外，if从句还‎表示不可实‎现的条件或‎根本不可能‎存在的条件‎，也就是一种‎虚拟的条件‎或假设。

从句多用一‎般过去时或‎过去完成时‎，表示对现在‎或过去的一‎种假设。

如：If I were you，I would‎invit‎e him to the party‎．如果我是你‎，我会邀请他‎参加聚会。

(不能用wa‎s)I would‎have arriv‎e d much earli‎e r if I had not been caugh‎t in the traff‎i c．要不是交通‎堵塞，我本会来得‎早一些。

另外你还要‎注意if 条件句的时‎态搭配1．if从句用‎一般现在时‎，主句用一般‎将来时If he runs ，he’ll‎get‎there‎in time.如果他用跑‎的，他就会及时‎赶到那儿。

The cat will scrat‎c h you if you pull her tail.如果你拉猫‎的尾巴，它就会抓你‎。

2. if从句用‎一般现在时‎，主句用ma‎y/might‎/canIf the fog gets thick‎e r the plane‎may/might‎be diver‎t ed.如果雾在大‎一些，飞机可能就‎会改在别的‎机场降落。

初中条件状语从句(附答案)条件状语从句是由连接词if或unless引导的从句。

在含有条件状语从句的复合句中，如果主句是一般将来时态，从句要用一般现在时。

if和unless是常用的引导词。

if引导的条件状语从句有真实条件句和非真实条件句两种。

真实条件句表示在某种条件下某事很可能发生，而非真实条件句是虚拟语气的一种，表示与事实相反、不可实现的条件或根本不存在的条件。

在真实条件句中，if后面的从句要紧跟着，放在前面，逗号要放在句中间。

主句多用将来时。

在非真实条件句中，从句多用一般过去时或过去完成时。

unless是if。

not的固定搭配，意为除非、若不、除非在。

的时候。

例如，You will fail to arrive there in time unless you start earlier。

= If you don't start earlier。

you will fail to arrive there in time。

除非你早点动身，否则你就不能及时赶到那儿。

1.If you feel tired。

you have to have a rest.2.Where will he see the film if he has time?3.If there were fewer trees。

there would be XXX.4.XXX if he did not work on XXX.5.If Marcia lived alone。

she would keep a pet parrot.na will buy a new dress if the old one is out of style.7.XXX.If we _____________ a birthday party for him。

everyone_____________ come。

8.I would have a bake sale if I XXX。

初中英语：条件状语从句一. 条件状语从句的概念条件状语从句，即在某种条件下，一件事情可能发生。

在英语中由连接词if或unless等引导的状语从句叫做条件状语从句。

条件是指某一件事情实现之后（状语从句中），一件事情（主句）才能发生，通常译作假如，只要，如果”等意思。

条件状语从句中，主从句的时态要遵循生将从现”的原则。

即，主句是将来时态时，从句用一般现在时代替将来时态。

二. 条件状语从句的引导词1.If conj .如果，假如If you ask him , he will help you . 如果你请他帮忙，他会帮你的。

If you fail in the exam , you will let him down . 如果你考试不及格，你会让他失望的。

2. ............................................................ unless conj.除非，若不，除非在的时候（if...not...）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。

3. so/as long as conj. 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。

三. 关丁条件句的时态，常见的有以下三种情况：1、条件状语从句的主句是一般将来时，那么从句常常用一般现在时。

When I grow up, I ' ll be a nurse and look after patients.我长大后要当一名护士，照顾病人。

2、如果主句是祈使句，那么从句通常要用一般现在时。

if 引导的条件状语从句（讲义）状语用来表示行为发生的时间、地点、目的、方式、程度等，通常由副词或介词短语充当，也可由一个句子充当。

I slept at home yesterday because I had a bad cold.状语从句状语从句指句子作状语。

根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式等从句。

状语从句一般由连词(从属连词)引导。

I will go to school by bike tomorrow if it is sunny.Grammar focus—I think I’ll take the bus to the party.—If you do, you’ll be late.If you take the bus to the party, you’ll be late.—I think I’ll stay at home.—If you do, you’ll be sorry.If you stay at home, you’ll be sorry.—What will happen if they have the party today?—If they have it today, half the class won’t come.—Should we ask people to bring food?—If we ask people to bring food, they’ll just bring potato chipsand chocolate.1.if 在本单元句中意为“；”，用于引导即 if 引导的是一个完整的句子，所以一定要有主谓，成为从句，另一个句子则成为主句。

If you go there, I’ll go, too.We will go hiking if it doesn’t rain tomorrow.If Bob leaves tomorrow, I will hold a party for him tonight.2.if 引导的条件状语从句既可以放在主句前，也可放在主句后。

If 引导的条件状语从句讲解与练习If引导条件状语从句的条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的。

如：If you ask him，he will help you．如果你请他帮忙，他会帮你的。

If you fail in the exam，you will let him down．如果你考试不及格，你会让他失望的。

If you have finished the homework，you can go home．如果你作业做完了就可以回家了。

1．if从句用一般现在时，主句用一般将来时If he runs he’ll get there in time.如果他用跑的，他就会及时赶到那儿。

The cat will scratch you if you pull her tail.如果你拉猫的尾巴，它就会抓你。

2．if从句用一般现在时，主句用may/might/can/must/shouldIf it stops snowing we can go out. 如果雪停了，我们就可以出去。

If you want to lose weight you must/should eat less bread.如果你想减肥，你必须少吃面包。

(另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。

从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。

如：If I were you，I would invite him to the party．如果我是你，我会邀请他参加聚会。

I would have arrived much earlier if I had not been caught in the traffic．要不是交通堵塞，我本会来得早一些。

)If条件状语从句练习( )1. If I find his phone number, I ______ you.A. tellB. toldC. will tellD. have told( )2. I __ the CDs to you if I have time tomorrow.A．will return B. returned C. have returned D. return( )3. The students will go to the Summer Palace if it ________tomorrow.A. won' t rainB. isn' t rainingC. doesn' t rainD. isn' t rain ( )4. I won’t watch the TV play if my father ___ me do my homework.A. letB. will letC. won’t letD. lets( )5. If you ___quiet, I’ll tell you what happened.A. willB. are C are to be D be( )6. If you go to the party, you ___ a good time.A. would haveB. haveC. will haveD. had( )7. Don’t worry. Peter will call you as soon as he _____ London.A. will get toB. gets toC. get toD. got to( ) 8.He doesn’t tell me when he __. I’ll telephone you as soon as he ___.A. will come, comesB. will come, will comeC. comes, will comeD. comes, comes( )9.-- I don’t know if Dr. White ______ to the party next week.–-- I think he will come if he ______ free.A. comes; will comeB. will come; will beC. comes; isD. will come; is( )10. I don’t know if there ____ a sports meeting next month. If they _____ it, I must get ready for it.A. is; will holdB. will be; holdC. will be; will holdD. will have; hold宾语从句练习( ) 1. I don’t know ___________________.A. what does he like bestB. what he like bestC. what he does like bestD. what he likes best( ) 2. Can you tell me ______________________?A. where she livesB. where does she liveC. she lives whereD. where she live( ) 3. He asked me _______________________________.A. what time is itB. what time it isC. what time was itD. what time it was( ) 4. Do you know _______________________?A. how much did it costB. how much it did costC. how much it costsD. how much does it cost( ) 5. The man asked her _______________________.A. why did she do itB. why she did itC. why she doesD. why does she do it( ) 6. Nobody knows _________________________.A. when will she come backB. when she come backC. when she will come backD. when does she come back ( ) 7. Mum asked _______________________________.A. where he wasB. where was heC. where he isD. where is he( ) 8. Do you know _______________________________?A. what they are looking forB. what are they looking forC, they are looking for what D. what do they look for ( ) 9. The teacher asked ________________________________.A, who can answer this questionB. who could answer the questionC. what question did she askD. she answered this question( ) 10. I asked her ______________________________.A. whether he has been to AustraliaB. whether has he been to AustraliaC. whether he had been to AustraliaD. whether he goes to Australia( ) 11. The teacher told us ________________________________.A. that light traveled faster than soundB. if light traveled faster than sound.C. that light travels faster than soundD. if light travels faster than sound( ) 12. He said that __________________________________.A. he is doing his homeworkB. he does his homeworkC. he was doing his homeworkD. he do his homework( ) 13. I asked him _________________________.A. where did he goB. where he wentC. where does he goD. where he did go( ) 14. --Excuse me, could you tell me _____ get to the plane?--Certainly. Go straight alone here.A. how can weB. how we canC. when can weD. when we can( ) 15. Do you know _____he will ride here at 8 tomorrow morning?A. whenB. whereC. whetherD. how( ) 16. --Can you tell me why __________________?--Because I want to help the people there.A. do you go to TibetB. did you go to TibetC. are you going to TibetD. you are going to Tibet ( ) 17. Do you know _______________________________?A. what time does the train leaveB. what time leaves the trainC. what time the train leaveD. what time the train leaves( ) 18. Could you tell me _______________________?A. who is heB. where’s the nearest restaurantC. if he will come tomorrowD. which way is to the underground station( ) 19. --Do you know ___________?--Sorry. I don’t know. You may ask the woman over there.A. when the shop opensB. when is the shop openC. when does the shop openD. when will the shop open ( ) 20 --Dad, do you know ____________? --In half an hour.A. when will the football game startB when the football game will startC. when is the football game going to startD. when shall we start the football game( ) 21. Could you tell me _______________________?A. which bus they are waiting forB. which bus are they waiting forC. they’re waiting for which busD. which bus they wait( ) 22. I asked her __________________________.A. whether did she like the red oneB. whether she likes the red oneC. whether does she like the red oneD. whether she liked the red one( ) 23. Can you guess (猜）__________the people in the picture are ?A. whenB. whomC. whoseD. who( ) 24. I’m thinking about ________________________________.A. if I’ll help herB. whether I’ll help herC. what I’ll help herD. that I help her( ) 25. --We never know _____________. --They say he is a teacher.A. what the old man isB. what is the old manC. who is the old manD. which the old man is40aaaaa 学生缴费日期表aa。