if引导的条件状语从句
（一）定义
if引导的句子在复合句中表示条件，假如if从句的动作发生，主句的动作就（不）会发生，因此称为条件状语从句。
（二）位置
if 引导的条件状语从句位置灵活，可直接放在主句后面，也可以放在句首。放在句首时，从句后面要用逗号和主句隔开。
① If I have enough money, I will travel around the world.
② I will travel around the world if I have enough money.
（三）用法
① Work hard, and you’ll pass the exam easily. 努力学习，你将很容易通过考试。
→If you work hard, you’ll pass the exam easily.
② Hurry up, or you’ll miss the train. 快点儿，否则你就赶不上火车了。
→If you don’t hurry up, you’ll miss the train.
（3）当主句含有情态动词时，if引导的条件状语从句通常用一般现在时。
We must study hard if we want to pass the final exam.
如果想通过期末考试，我们必须努力学习。
（4）用含介词with或without的介词短语转换。
① If you help me, I'll finish my job soon.
→With your help, I'll finish my job soon. 如果你帮我，我将很快完成我的工作。
② If there is no water, fish can’t live.
→ Fish can’t l ive without water. 离开水，鱼不能生存。
（四）if引导的条件状语从句与if引导的宾语从句的区别
if引导宾语从句时表示“是否”，位于及物动词之后；
if引导的条件状语从句时表示“假如，如果”，位于句首或句中。
①I don't know if he will come tomorrow.
②If he comes, I'll call you.
练习
一、选择题
1. _____ you don't go to bed earlier, you will feel tired in the morning.
A. Unless
B. If
C. Though
D. Until
2. Why not look up the new word in a dictionary _____ you don't know it?
A. if
B. that
C. though
D. whether
3. Talk to your teacher and you will get help _____ you have a problem.
A. unless
B. if.
C. until
D. so
4. I won't go to tomorrow's party _____ I'm invited.
A. if
B. unless
C. when
5. The children will climb the hill if it _____ tomorrow.
A. won't rain
B.didn't rain
C. isn't raining
D. doesn't rain
6. We wonder if our teachers _____ to our graduating party next weekend. If they_____, we'll be very happy.
A. will come; will come
B. come; will come
C. will come; come
D. come; come
二、翻译句子。
1. 如果明天下雨，我们将在家看电视。
We'll stay at home watching TV if it _____ （rain）tomorrow.
2. 如果她早点起床，就有时间在家里吃早餐.
If she ______ _______ a little earlier, she ‘ll have time to eat breakfast at home.
3. 如果你参加聚会，你将会过得很开心。
If you ______ the party, you ______ ______ a great time.
4. 如果你经常听英文歌，你将会喜欢英语。
If you often ______ ______ English songs, you ______ _______ English.
一、BABBDC
二、1. rains 2. gets up 3. join, will have 4. listen to, will like
t 条件状语从句 一、 条件状语从句通常由 if （如果）, unless （除非），as long as （只要）引导。 例如：If it rains tomorrow, we won ’go to the park. 如果明天下雨，我们就不去公园了。 Unless weather stops me, I go for a walk every. 我每天都会去散步，除非遇上坏天气。 Our parents will be pleased with our performance as long as we try our best. 小试牛刀：1、只要我们竭尽全力，父母就会满意我们的表现。 Our parents will be pleased with our performance _____ _____ ______ we try our best. 2、如果人人为保护环境做出贡献，世界将会变得更美好。______ ______ ______ _____ _______ to protecting the environment, the world will become much more beautiful. 二、if 引导的条件状语从句 （1）“if 从句+祈使句”的句子。其实，if 作为一个连词，主句也可以是其他形式的句子。 例如：If you want to go, please let me know. If the green light isn ’t on, wait for a minute. (2)“祈使句 + and (or)+ 陈述句” 在意思上相当于一个带有条件状语从句的复合句。 注意：A. “祈使句 + and + 陈述句”可以转化为 if 引导的肯定条件状语从句，而且主语是第二人称。 B. “祈使句 + or + 陈述句”可以转化为 if 引导的否定条件状语从句，而且主语是第二人称。 例如：Study hard and you will pass the exam. =If you study hard, you will pass the exam. Hurry up, or you ’ll be late. =If you don ’t hurry up, you ’ll be late. 考题 (2010 重庆中考)Work hard ，________ you may catch up with your classmates soon. A.or B.but C.and D.yet 思路解析：本句是“祈使句＋and”的句型，句意为“努力学习，你会很快赶上其他同学的”，and 在句中表示承接 关系，所以选 C 项。答案：C 黑色陷阱：本题的陷阱是句型，本句型区别于“祈使句＋or”，这个句型的含义是“……，不然的话/否则……”。 绿色通道：祈使句后面既可以加 and ，也可以加 or ，所以要全面分析句意，再作决定。 小试牛刀：用 if 连接下列句子 1、Go to bed early and you will have a good rest. 2、Hurry up, or you ’ll miss the bus. 三、if 从句与主句具有以下特点： 1．If 从句中用一般现在时，表示未来的一种条件，从句中可以加时间状语。 e.g.If yo u can’t come tomorrow, we can hold the party a little later.明天你如果不能来，我们可迟一点举行宴会。
If条件状从句练习 1. 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 2. I’m waiting for my friend._, I'll go shopping alone. A. If she comes B. If she won't come C. If she doesn't come 3.The students ____ have a sports meeting this weekend if it _____。A. won’t; rains B. will; rains C. won’t; will rain D. are going to; is going to rain 1.If you _____ to the party, you’ll have a great time A. will go B. went C. go D. going 2.–What are you going to do tomorrow? --We’ll go to the library tomorrow if it ___. A. isn’t rain B. rain C. won’t rain D. doesn’t rain 3. What will you do if you _____ to the old folk’s home visit? A. go B. went C. going D. will go 4. If I eat ____ food, I’ll be very fat. A. too many B. many too C. too much D. much too 5. I’ll give the book to him if he ___ here next Sunday. A. will come B. comes C. is coming D. came 6. I ____ her the answer if she ____me. A. can tell, will ask B. will tell, will ask C. would tell, ask D. will tell, asks 7. We’ll go to the farm and help the farmers with the apple-picking if it ____ tomorrow. A. won’t rain B. will be rainy C. doesn’t rain D. isn’t raining 8. There is going to _______ a sports meeting next week. If it ________, we’ll have to cancel it. A. be, will rain B. have, will rain C. be, rains 9. Y our teacher will be unhappy if you _______ to school late. A. come B. will come C. are coming D. came 10．I don’t know if he __. If he __ , please let me know. A. comes, comes B. will come, will come C. will come, comes D. comes, will come 11．Y ou will stay healthy _______ you do more exercise, such as running and walking. A. if B. how C. before D. where 12.If she here tomorrow, I will tell you. A. comes B. will come C. come D. came 13. I’m waiting for my friend. , I’ll go shopping alone. A. If she comes B. If she doesn’t come C. If she won’t come 14. —Tom wants to know if you will have a picnic tomorrow. —Y es. But if it ______, we’ll play chess instead. A. will rain B. rained C. is raining D. rains 15. If Tom _____ the game, we'll give him a surprise". A. win B. wins C. won D. miming 二、用所给词的适当形式填空。 1.If you ________(feel) tired, you _________ (have) to have a rest. 2. Where _____ he ____(see) the film if he _________(have) time? 3. If there ____(be) fewer trees, there _______( be) more pollution. 4. He ___(dress) more casually if he ___( not work) on weekends. 5. If Marcia _______(live) alone, she _______( keep) a pet parrot. 6. Lana _____ buy) a new dress if the old one ____(be) out of style. 7.The twins _______(fight) if they__________(argue). 8. I ______(have) a bake sale if I ____(need) money for education.
If条件句专练 I单项选择 1. If he hard, he will get good grades. A. study B. studies C. will study D. studied 2. I want to know if Mary to the party tomorrow. A. go B. went C. will go D. goes 3. Everyone must dress up. If you, they won’t let you in. A. don’t B. won’t C. can’t D. mustn’t 4. Mary will go to Sanya if she a five-day trip. A. have B. had C. will have D. has 5. If he comes late,he will miss the train.
A. and B. so C. / D. or II用所给词的适当形式完成句子 1. If Bruce ________(be) free, Let’s go to the park. 2. Tell him the news if you ________ ( meet ) him tomorrow. 3. If he ________(do) well in the exam. His teacher will be pleased with him. 4．If Mary ______(leave ) home too long, she ________(miss) her parents. 5. Be quick ,and you _________(arrive) in time. 6. Hurry up, or you_________(be ) late for school. III完成句子 1.如果他到的晚了会发生什么事情? What _______________ if he _____________ late? 2.如果努力学习,你就会取得好成绩. If you_________ ________,you ________ good ___________. 3.他如果看电视太久了,他的父母会不高兴. If he _____ TV too much, his parents _____ _________unhappy. 4.如果我们为他组织生日聚会,大家都会来的. Everyone ________ if we _______a birthday party ________ him. 5.如果明天不下雨,我会和你一起去公园的.
if引导的条件句中的虚拟语气 虚拟语气表示一种不能实现的假设。该语法主要用于if条件状语从句。 一、if引导的条件状语从句的分类及虚拟条件句的判断 1、可以把条件句分为两类： 1).真实条件句（Sentences of Real Condition）：凡是假设的情况发生性可能很大，就是真实条件句。例如： ⑴、If I have time , I will help you with this work.如果我有时间会帮助你做此工作的。 (2)、If time permits, we'll go fishing together.(如果有时间的话，我们就一起去钓鱼。） 2).虚拟条件句（Sentences of Unreal Condition）：当假设是不大可能实现时，就是虚拟条件句。例如： ⑴、If I were you , I would have attended the meeting. 如果我是你的话，就去参加会议了。 ⑵、If he had come here yesterday, he would have seen h is old friend.假如他昨天来这儿的话，就会看见他的老朋友。 ⑴、If it had rained yesterday, we would have stayed at home.（如果昨天下雨的话，我们就会留在家里。） 2、.if条件状语从句中虚拟语气的判断 判断是真实条件句还是非真实条件句。只有在非真实条件句中才使用虚拟语气。通过句子意思，看假设的条件是否能够实现，能
够实现是真实条件句，不能使用虚拟语气；假设的条件不能实现则是非真实条件句，要用虚拟语气。 判断这个假设是与哪个事实相反。通常有三种情况：①与过去事实相反。②与现在事实相反。③与将来事实可能相反。 3、“后退一步法” 后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中，谓语动词按正常情况“后退一步”。也就是： ①与过去事实相反，在从句中用过去完成时形式表示。 ②与现在事实相反，在从句中用过去一般时形式表示。 ③与将来事实可能相反，在从句中用过去将来时形式表示。 主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。例： ⑴、If I had come her yesterday, I would have seen him. ⑵、If I were a teacher, I would be strict with my stud ents. ⑶、If it should snow tomorrow, they couldn't go out. 4、注意事项 ①if条件句中如有were, should, had，可以省去if，并使用倒装语序。 ②在现代英语中if条件状与从句中的谓语动词如果是be其过去形式一般用were。
If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/can If 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/should 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。 4．if从句用一般现在时，主句用一般现在时 If you heat ice it turns to water. (也可用will turn)如果把冰加热，它就会化成水。5．if从句用现在进行时，主句用一般将来时 If you are looking for Peter you’ll find him upstairs. 如果你是在找彼得，上楼就会找到他。 6．if从句用现在完成时，主句用一般将来时 If you have finished dinner I’ll ask the waiter for the bill. 如果你吃完了，我就叫服务生来算账 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。 条件句表可能，主句多用将来时； 条件句表事实，主句常用现在时。
if_条件状语从句的时态练习及答案_初中习题集 I.单项选择 1.If you _____ to the party, you’ll have a great time. a. will go b. went c. go d. going 2.It will be a long time ____ peter _____ his work. a. since, has finished b. after, finishes c. when, will finish d. before, finishes. 3. what will father _____ us from Japan? a. take b. bring c. carry d. make 4. Weifang is famous ______ kites a. for b. to c. on d. with 5． I____ her the answer if she ____me. a. can tell, will ask b. will tell, will ask c. would tell, ask d. will tell, asks 6. – what are you going to do tomorrow? --we’ll go to the library tomorrow if it ___. a. isn’t rain b. rain c. won’t rain d. doesn’t rain 7.—Do you know when he will come back tomorrow? --sorry, I don’t know. when he ____ back, I’ll tell you. a. comes b. will come c. come d. may come 8. what will you do if you _____ to the old folk’s home visit? a. go b. went c.going d. will go 9. If I eat ____ food, I’ll be very fat. a. too many b. many too c. too much d. much too 10.I’ll give the book to him if he ___ here next sunday. a. will come b. comes c. is coming d. came 11. There ____an english film in our school tomorrow. a. is going to have b. will have c. is going to be d. has 12.Could you tell us where ____？ a. will the next olympic games held b. the next olympic games will be held c. would the next olympic games be held d. the next olympic games would be held 13. When my mother returned last night,I ____ a book. a. read b. am reading c. was reading d. am going to read 14. What ____ you ____ when it began to rain? a. do, do b. were, doing c. are, doing d. did, do 15. I’ll wake you up when he ____back. a. will b. is going to come c. comes d. come II、用所给词的适当形式填空 1.If you _______(feel) tired, you ______(have) to have a rest. 2. Where _____ he ______(see) the film if he ________(have) time?
If条件状语从句专练 1. If I ___(go) to the party, they ___(be) upset. 2. If I ___(take) a taxi, it ___(be) too expensive. 3. If she ___(finish) work early, she can go home. 4. If the weather is fine, we ____(go) for a walk. 5. If I ___(have) time tonight, I will finish the book. 6. If it ___(rain) next Sunday, we won`t be able to plant trees. 7. If she ___(arrive) home, she will phone
me. 8. Unless you speak to him first, she ___(not speak) to you. 9. If he ___ (call) to you, tell him I will ring back. 10. I don`t know if it ___(rain) tomorrow. 11. Have a rest if you ___(be) tired. 12. Don`t come unless I ___(call) you. 13. I don`t know if he ___(come) tomorrow, but if he __(come), I`ll let you know. 宾语从句与状语从句混合 1. ——Helen, do you know if Martin
Unit 4 一. if 条件句 if可以引导真实条件句和虚拟条件句。真实条件句表示在假设的条件下，能够实现的情况。在这种情况下，主句和从句的谓语动语随各自的人称和时态发生变化，同时if条件句遵循“主将从现”的原则，即主句用一般将来时，从句用一般现在时表将来。 If it doesn’t rain tomorrow, we will go for a picnic. 如果明天不下雨，我们去野餐。 如果if条件句用来描述说话人认为与事实相反的内容，或仅是一种愿望，假设、猜测等，我们称为虚拟条件句。 If I got rich , I would travel around the world. 如果我有钱了，我将周游全世界。 二.虚拟语气 区分条件从句主句例句 ★与现在事实相反If+主语+过去 式（be多用 were）… 主语+would/should/could/ might+动词原形… If I were rich, I would buy a big house. 如果我 有钱，我将买一所大房 子。 与过去事实相反If+主语+had+ 过去分词… 主语 +would/should/could/might+ have+过去分词… If I had read this article earlier, I would not have made this kind of mistake.如果我早读过这 篇文章，我就不会犯这 样的错误了。 与将来事实相反If+主语+过去 式（be多用 were） /should+动词 原形/were to+ 动词原形… 主语 +would/should/could/might+动 词原形… If it were to rain tomorrow, the match would be put off. 如果明 天下雨，比赛就会被推 迟。
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 一、用所给词的适当形式填空 1.If you ________(feel) tired, you _______________ (have) to have a rest. 3. If there __________(be) fewer trees, there _______________( be) more pollution. 5. If Marcia _____________(live) alone, she ___________________( keep) a pet parrot. 6. Lana ________________( buy) a new dress if the old one ____________(be) out of style. 9. Peter _____________( send) me a beautiful souvenir if he ________________(tour) Spain. 10. If Mr Green ___________(say) I am hard- working, my parents _________( feel) glad. 11.I ____________(go) to the beach if it________________ ( not rain) this week. 13.He ____(write) a letter to his grandparents if he ____(get) his report card this week. 14. If she ____________(get) up late, she _____________ ( not catch) the early bus. 15. Peter ________(major) in English if he ____(pass) the exams in Peking University. 16. 如果努力学习，你就会取得好成绩。 If you__________ _________, you ___________ good _____________. 17. 他如果看电视太久了，他的父母会不高兴。 If he _________ TV too much, his parents __________ __________ unhappy. 18. 如果我们为他组织生日聚会，大家都会来的。 Everyone ________________ if we _____________ a birthday party __________ him. 19. 如果明天不下雨，我会和你一起去公园的。 If it __________ __________ tomorrow, I ______________ go to the park _________ you. 21. 如果他有空，他会帮助你的。 If he _________________, he _________________ you. 23. 你如果抄同学的作业就不能学好各门功课。 You _______ _____ good at all the subjects if you ______ the other students’ homework. Ⅰ.单项选择（15分） 1.If you _____ to the party, you’ll have a great time. A. will go B. went C. go D. going 2. It will be a long time ____ Peter _____ his work. A. since, has finished B. after, finishes C. when, will finish D. before, finishes. 3. What will father _____ us from Japan? A. take B. bring C. carry D. make 4. Weifang is famous ______ kites. A. for B. to C. on D. with 5．I ____ her the answer if she ____me. A. can tell, will ask B. will tell, will ask C. would tell, ask D. will tell, asks 6. – What are you going to do tomorrow? --We’ll go to the library tomorrow if it ___. A. isn’t rain B. rain C. won’t rain D. doesn’t rain 7.—Do you know when he will come back tomorrow? --Sorry, I don’t know. When he ____ back, I’ll tell you. A. comes B. will come C. come D. may come 8. What will you do if you _____ to the old folk’s home visit? A. go B. went C.going D. will go 9. If I eat ____ food, I’ll be very fat.
if引导的条件状语从句 （一）定义 if引导的句子在复合句中表示条件，假如if从句的动作发生，主句的动作就（不）会发生，因此称为条件状语从句。 （二）位置 if 引导的条件状语从句位置灵活，可直接放在主句后面，也可以放在句首。放在句首时，从句后面要用逗号和主句隔开。 ① If I have enough money, I will travel around the world. ② I will travel around the world if I have enough money. （三）用法 ① Work hard, and you?ll pass the exam easily. 努力学习，你将很容易通过考试。 →If you work hard, you?ll pass the exam easily. ② Hurry up, or you?ll miss the train. 快点儿，否则你就赶不上火车了。 →If you don?t hurry up, you?ll miss the train. （3）当主句含有情态动词时，if引导的条件状语从句通常用一般现在时。 We must study hard if we want to pass the final exam. 如果想通过期末考试，我们必须努力学习。 （4）用含介词with或without的介词短语转换。 ① If you help me, I'll finish my job soon. →With your help, I'll finish my job soon. 如果你帮我，我将很快完成我的工作。 ② If there is no water, fish can?t live. → Fish can?t l ive without water. 离开水，鱼不能生存。 （四）if引导的条件状语从句与if引导的宾语从句的区别 if引导宾语从句时表示“是否”，位于及物动词之后； if引导的条件状语从句时表示“假如，如果”，位于句首或句中。 ①I don't know if he will come tomorrow. ②If he comes, I'll call you. 练习 一、选择题 1. _____ you don't go to bed earlier, you will feel tired in the morning. A. Unless B. If C. Though D. Until 2. Why not look up the new word in a dictionary _____ you don't know it? A. if B. that C. though D. whether 3. Talk to your teacher and you will get help _____ you have a problem. A. unless B. if. C. until D. so 4. I won't go to tomorrow's party _____ I'm invited. A. if B. unless C. when 5. The children will climb the hill if it _____ tomorrow.
滨淮农场学校九年级英语专题复习三：if引导的条件状语从句 一、用所给词的适当形式填空 you _______(feel) tired, you ____________ (have) to have a rest. 2. If there ________(be) fewer trees, there ____________( be) more pollution. 3. If Marcia __________(live) alone, she ____________( keep) a pet parrot. 4. Lana _______( buy) a new dress if the old one _________(be) out of style. 5. Peter ________( send) me a beautiful souvenir if he __________(tour) Spain. 6. If Mr Green _____(say) I am hard- working, my parents ________( feel) glad. 二、单项选择 （）you _____ to the party, you’ll have a great time. A. will go B. went C. go D. going （）2. It will be a long time ____ Peter _____ his work. A.since, has finished B. after, finishes C. when, will finish D. before, finishes. （）3. I ____ her the answer if she ____me. A. can tell, will ask B. will tell, will ask C. would tell, ask D. will tell, asks （）4. – What are you going to do tomorrow --We’ll go to the library tomorrow if it ___. A. isn’t rain B. rain C. won’t rain D. doesn’t rain （）5.—Do you know when he will come back tomorrow --Sorry, I don’t know. When he ____ back, I’ll tell you. A. comes B. will come C. come D. may come （）6. What will you do if you _____ to the old folk’s home v isit A. go B. went D. will go （）7. If I eat ____ food, I’ll be very fat. A. too many B. many too C. too much D. much too （）8. I’ll give the book to him if he ___ here next Sunday. A. will come B. comes C. is coming D. came
If 引导的一般条件状语从句 --------By the teacher: Jerry Zhang 条件状语从句 概念：在复合句中，由从句表示的状语叫做状语从句。它可以用来修饰主语中的动词.形容词.副词等。根据它表达的意思，状语从句可以分为时间状语从句，地点状语从句，条件状语从句，比较状语从句，目的状语从句，结果状语从句和让步状语从句等。由连接词if或unless引导的状语从句叫做条件状语从句。（注意：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[主将从现原则] 经典语句：If it doesn't rain tomorrow, we will go to the zoo. If you open the door，I will come in. if 引导的条件状语从句 主句用一般将来时，if 从句用一般过去时。 We will go to the park if it is fine tomorrow.如果明天天好的话我们就去公园。 We will go traveling if we have time tomorrow.如果明天我们有时间我们就去旅行。 主句祈使句，if 从句用一般现在时。 Please call me if you need help. 如果你需要帮助请打电话给我。 Sing a song if you feel happy. 如果感到快乐就唱首歌吧！ 主句含有情态动词，if 从句用一般现在时。 You can make a lot of money if you run a company.如果你经营一家公司的话你会装很多钱。 You can get number one if you study hard. 如果你努力学习你就可以得第一。 —Mary, what about going boating if it doesn’t rain? 玛丽，如果明天不下雨，我们就划船好吗？ —Good idea. 好主意。 Unit5练习题：单词 1. If you wear your j___________ to school, the teacher won’t let you in. 2. If you bring food to school, the teacher will t_________ it away. 3. If you are on duty, you must c____________ up the classroom. 4. The f__________ in the garden smells nice. 5. I want to have a birthday party, please help me o___________ it.
初中英语――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/can If 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/should 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。4．if从句用一般现在时，主句用一般现在时 If you heat ice it turns to water. (也可用will turn)如果把冰加热，它就会化成水。 5．if从句用现在进行时，主句用一般将来时 If you are looking for Peter you’ll find him upstairs. 如果你是在找彼得，上楼就会找到他。6．if从句用现在完成时，主句用一般将来时 If you have finished dinner I’ll ask the waiter for the bill. 如果你吃完了，我就叫服务生来算账 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 can't 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