if用法归纳
if句型的用法总结
if句型的用法总结1. if句型的基本用法if句型是英语中最常用的条件句句型之一，它用于描述一个条件成立时会发生什么样的结果。
基本的if句型结构为：if 条件:条件成立时执行的代码块在这个结构中，条件决定了是否执行代码块的部分。
如果条件成立，代码块将会被执行；如果条件不成立，则代码块将会被忽略。
2. if…else句型除了基本的if句型外，还有一个常见的变体——if…else句型。
它在条件成立时执行一个代码块，并在条件不成立时执行另一个代码块。
其结构如下：if 条件:条件成立时执行的代码块else:条件不成立时执行的代码块在if…else句型中，如果条件成立，将执行if代码块；否则，将执行else代码块。
3. if…elif…else句型在某些情况下，我们可能需要判断多个条件，并根据不同的条件执行不同的代码块。
这时，可以使用if…elif…else句型。
其结构如下：if 条件1:条件1成立时执行的代码块elif 条件2:条件2成立时执行的代码块elif 条件3:条件3成立时执行的代码块...else:条件都不成立时执行的代码块在if…elif…else句型中，只有当前面的条件不成立时才会判断后面的条件。
如果某个条件成立，将执行对应的代码块。
如果所有条件都不成立，将执行else代码块。
4. 嵌套if语句在某些情况下，我们可能需要在if代码块中再次使用if语句，这就是嵌套if语句。
嵌套if语句可以用于处理更复杂的条件判断。
例如：if 条件1:if 条件2:条件1和条件2同时成立时执行的代码块else:条件1成立，但条件2不成立时执行的代码块else:条件1不成立时执行的代码块在嵌套if语句中，内部的if语句只有在外部if语句的条件成立时才会被执行。
5. if语句的注意事项•条件表达式:–条件表达式应该是一个布尔表达式，即可以判断为真或假的表达式。
–可以使用比较运算符（如==、!=、<、>等）、逻辑运算符（如and、or等）以及其他返回布尔值的函数或表达式作为条件。
if的用法归纳总结
if的用法归纳总结if是英语中常用的一个连词，用于表达条件、假设或可能性。
它在句子中起到连接不同语义部分的作用，使得句子更加完整、清晰。
以下是对if的用法进行归纳总结：1. 表达现实条件：- if引导的主句表示现在或将来的真实条件，从句使用一般现在时态。
例：If it rains tomorrow, we will stay at home.- if引导的主句表示过去的真实条件，从句使用一般过去时态。
例：If she was tired yesterday, she went to bed early.2. 表达虚拟条件：- if引导的主句表示与事实相反的条件，从句使用过去完成时。
例：If I had studied harder, I would have passed the exam.- if引导的主句使用过去完成时，从句使用过去完成时进行的虚拟条件。
例：If he had arrived earlier, we would have caught the train.3. 表达将来可能性：- if引导的主句表示将来可能发生的条件，从句使用一般现在时态。
例：If it snows tomorrow, we will go skiing.4. 表达建议或要求：- if引导的主句表示建议或要求，从句使用一般现在时态。
例：If you have any questions, please ask.5. 表达假设：- if引导的主句表示假设，从句使用一般现在时态。
例：If I were you, I would apologize.6. 表达条件连词短语：- if引导的主句与从句之间有条件连词短语，从句使用一般现在时态。
例：If it is sunny tomorrow, we can go to the beach.7. 使用whether替代if：- 当表示是否的意思时，可以使用whether替代if。
if虚拟语气的用法归纳
if虚拟语气的用法归纳IF虚拟语气是英语中的一种重要语法现象，主要用于表示与现实相反的假设、愿望、建议等。
它分为两种形式：if条件句和if非条件句。
以下是对IF虚拟语气用法的详细介绍：一、if条件句1. 表示与现在事实相反的假设：If + 主语+ 过去时态，主语+ would/could/might/should + 动词原形。
例如：If I were you, I would go to the party.（如果我处在你的位置，我会去参加派对。
）2. 表示与过去事实相反的假设：If + 主语+ had done，主语+ would/could/might/should + have done。
例如：If he had come to the meeting, he would have known the plan.（如果他参加了会议，他就会知道这个计划。
）二、if非条件句1. 表示建议、劝告：主语+ should/would/might/ought to + 动词原形。
例如：You should go to the party.（你应该去参加派对。
）2. 表示愿望：主语+ could/would/might + 动词原形。
例如：I wish I were a bird.（我希望我是一只鸟。
）3. 表示假设：If + 主语+ 动词过去式，主语+ would/could/might + 动词原形。
例如：If I had time, I would go to the park.（如果我有时间，我会去公园。
）三、if虚拟语气的特殊结构1. 省略if，将were、had、should等词置于主语之前：主语+ were/had/should + 动词原形。
例如：She were here, she would meet him.（如果她在这里，她会见到他。
）2. 使用倒装结构：were/had/should + 主语+ 动词原形。
if作为如果的用法
if作为如果的用法"If" 是英语中的一个条件连词，表示“如果”、“假设”或“倘若”等意思。
它主要用于引导条件状语从句，表示某个条件成立时，主句的动作或状态就会发生。
以下是"if" 的一些基本用法：1. 基本形式：if + 条件状语从句，主句。
例如：- If it rains tomorrow, I will take an umbrella.（如果明天下雨，我会带伞。
）- If I have time, I will go to the movie with you.（如果我有时间，我会和你一起去看电影。
）2. 否定形式：if + 条件状语从句，主句+ not。
例如：- If he doesn't study hard, he won't pass the exam.（如果他不努力学习，他就不能通过考试。
）3. 疑问形式：if + 条件状语从句，主句+ 吗？例如：- If she likes dancing, does she go to the dance class?（如果她喜欢跳舞，她去上舞蹈课吗？）4. 短语搭配：- if only：表示对过去事物的愿望或遗憾，意为“要是……就好了”。
例如：- If only I had known about the party earlier.（要是早点知道这个派对就好了。
）- unless：表示除非某个条件成立，否则会发生某个结果。
例如：- Unless you hurry up, you'll be late for the train.（除非你快点，否则你会错过火车。
）- in case：表示以防万一，用于引导目的状语从句。
例如：- Bring an umbrella in case it rains.（以防下雨，带上伞。
）- on condition that：表示在某个条件成立的情况下，才会发生某个动作或状态。
虚拟语气if的用法
虚拟语气if的用法虚拟语气是英语中一个重要的语法现象，通过使用if引导的虚拟条件句来表达假设、愿望、建议或者表示与现实相反的情况。
以下是虚拟语气if的几种常见用法：1. 表达假设和假设的结果：使用虚拟语气if来表达假设和假设的结果，通常形如“If + 主语+ 动词过去式，主语 + would/could/might/could have + 动词过去分词”。
例句1: If I were rich, I would travel around the world.（假如我很有钱，我会环游世界。
）例句2: If it had rained, we could have stayed at home.（如果下雨的话，我们本来可以待在家里。
）2. 表达愿望：使用虚拟语气if来表达愿望，通常形如“If only + 主语 + 动词过去式”。
例句：If only I could speak fluent French.（要是我能流利地说法语就好了。
）3. 表达建议：使用虚拟语气if来表达建议，通常形如“If I were you, I would + 动词原形”。
例句：If I were you, I would take a break and relax.（如果我是你，我会休息放松一下。
）4. 表达对现在和过去不可能实现的条件：使用虚拟语气if来表达对现在和过去不可能实现的条件，通常形如“If + 主语 + had/could + 动词原形”。
例句1: If I had wings, I could fly in the sky.（如果我有翅膀，我就能在天空中飞翔。
）例句2: If I could play the piano, I would perform at the concert.（如果我会弹钢琴，我将会在音乐会上表演。
）总结起来，虚拟语气if的用法包括表达假设和假设的结果、愿望、建议以及对现在和过去不可能实现的条件。
if用法归纳
◇特别提醒1. if作为“是否”的用法初二课本暂时没有涉及，只作拓展之用。
2. 以下内容只作了解，现行牛津初中教材内容已经删除。
在表示某一情形总会出现相同的结果时，if从句和主句都用一般现在时。
If the engine gets too hot, it starts to smoke. 发动机过热就会开始冒烟。
3. if在虚拟语气中的用法为高中内容，比较复杂，在此不作涉及。
◇课本例句1. If you eat my food, I won’t talk to you. (P58)2. If I don’t have food, I will die. (P58)3. I f I don’t have food, I will die too. If I die, no one will look after you. (P58)4. If hunters catch a giant panda, they will kill it for its fur. (P60)5. If farmers cut down trees and forests, giant pandas will have nowhere to live. (P60)6. If people find baby pandas alone, they will often take them away. (P60)7. If we do nothing, soon there will be no giant pandas in the world! (P60)◇词典例句1. If we miss the last bus, we’ll have to walk home.2. If it rains, we’ll have to go indoors.3. If I have enough money next year, I will go to England.4. What shall we do if it rains tomorrow?5. She asked me if I was fond of music. 她问我是否喜欢音乐。
if用法归纳
◇课本例句1. If you eat my food, I won’t talk to you. (P58)2. I will die , I don’t have food, (P58)3. What shall we do if it rains tomorrow5. She asked me if I was fond of music. 她问我是否喜欢音乐。
6. Can you tell me if they’re planning to come 你能告诉我他们是否打算过来吗7. I don’t know if she’s coming. 我不知道她是否会来。
◇相关词组☆if you want/like如果你愿意的话You can come and stay with us if you want.☆if so如果是的话Are you planning to return to work, and if so, who is going to look after the baby☆if not如果不是的话Has anyone dealt with the technical problems And if not, why not☆if necessary/if possible 如果必要/可能的话We are ready to fight for our rights if necessary.I should like to be back here by 10:30 if possible.☆even if即使I’d rather never sell this painting, even if they offered me a million dollars.☆what if 要是……，那怎么办如果……那会怎样What if the boss walked in here now and saw us☆as if好像是……She always talks to me as if she was my sister.◇相关练习动词填空：1. If it ______ (be) sunny tomorrow, I ______( walk) to school .2. We ________ (not have ) our sports meeting if the weather ____ (not be ) fine.3. If it _______ (rain ), my father _____ (take ) me to school in his car .4. Tigers _______ (hunt ) for their own food if they _____ (live) in the wild.5. If wolves ________ (be) in the wild, they ______(live) as family groups.6. If we don’t help the wild animals in danger, they ______ (die) soon.单项选择：( ) don’t know if he ______ tomorrow . If he _______, I will tell him about it .A. will come; will comeB. comes ; comesC. comes; will comeD. will come ; comes( ) 2. If Simon ______ hard, he ______ good at English.A. work; isB. works; isC. works; will beD. will work; will be( ) 3. He will come ________ you ask him.A. whetherB. unlessC. ifD. while( ) 4. If the phone _______, can you answer itA. ringsB. is ringingC. will ringD. rang( ) 5. Please give me a ring if you _______next Sunday.A. wo n’t goB. don’t goC. not goD. not to go( ) you know if his school _____a sports meeting next month.A. holdB. holdsC. to ho ldD. will hold( ) are not sure if it ______tomorrow. If it ______, we won’t climb the South Hill.A. will now, snowsB. will snow, will snowC. snows, snowsD. snows, will snow( ) 8. If we do nothing, there_________ no more giant pandas.A. will haveB. will hasC.will be D. will be going to have( ) 9. There_________ elephants if we don’t protect them.A. won’t be anyB. will have noC. won’t be someD. will be some( ) 10. ---- Do you want to go swimming this afternoon----Yes, if the weather_________ warm.A. will beB. would beC. wasD. is翻译句子：1． If ___________________(如果明天不下雨的话), we will go to the zoo.2． __________________(如果你生病了), you must see the doctor. 3．You’ll have to have a rest _______________（如果你感到累）4． ___________________(如果我们训练海豚), they perform tricks. 5． Parrots repeat words _______________________ (如果你教他们) 6． _____________(如果老虎住在野外), they will hunt for their own food .7． If you do not hurry up, ________________________________.(你会上学迟到).◇江苏13城市中考试题汇编1. If those wild animals can’t find enough food, they ________ (die) or have to leave their habitat soon. (2010无锡)( ) 2. A tourist will easily lose his way in Beijing ______ he has a map or guide. (2010镇江)A. ifB.because C. unless D. when ( ) 3. ----Excuse me, could you take care of my little dog for me----________. I ________it if it doesn’t rain after supper. (09镇江)A. Sorry; will walkB. My pleasure; will walkC. I’m sure; walkD. I’m afraid not; walk( ) 4. I have the key to the front door. My parents won’t wait for me if I ___________ back late. (09徐州)A. comeB. will comeC. am coming D have come5. 如果明天下雨，我们就在家做作业。
if的用法总结
if的用法总结if的用法总结：if表示条件，意思是如果；if表示虚拟，意思是假如；if表示是否的含义，和whether相同用法，连接宾语从句。
扩展资料1.(表示条件)如果 ,主句用将来时,if从句用现在时表示将来He will come if you invite him.如果你请他,他会来的.2.(表示虚拟)假如,要是时态：可以表示过去,现在和将来的`情况.它的基本特点是时态退后.a.同现在事实相反的假设.句型：条件从句主句一般过去时 should( would) +动词原形If they were here,they would help you.b.表示于过去事实相反的假设.句型：条件从句主句过去完成时 should(would) have+ 过去分词If she had worked harder,she would have succeeded.The rice would not have been burnt if you had been more careful.If my lawyer had been here last Saturday,he would have prevented me from going.If he had come yesterday,I should / would have told him about it.含义：He did not come yesterday,so I did not tell him about it.If he had not been ill and missed many classes,he would have made greater progress.含义：He was ill and missed many lessons,so he did not make greater progress.c.表示对将来的假想句型：条件从句主句一般过去时 should+ 动词原形were+ 不定式 would + 动词原形should+ 动词原形If you succeeded,everything would be all right.If you should succeed,everything would be all right.If you were to succeed,everything would be all right.3.是否 = whether 连接宾语从句I wonder if she is ill.不知她是否病了.。
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1. If you eat my food, I won’t talk to you. (P58)2. I will die , I don’t have food, (P58)3. What shall we do if it rains tomorrow?5. She asked me if I was fond of music. 她问我是否喜欢音乐。
6. Can you tell me if they’re planning to come? 你能告诉我他们是否打算过来吗？7. I don’t know if she’s coming. 我不知道她是否会来。
◇相关词组☆if you want/like如果你愿意的话You can come and stay with us if you want.☆if so如果是的话Are you planning to return to work, and if so, who is going to look after the baby?☆if not如果不是的话Has anyone dealt with the technical problems? And if not, why not?☆if necessary/if possible 如果必要/可能的话We are ready to fight for our rights if necessary.I should like to be back here by 10:30 if possible.☆even if即使I’d rather never sell this painting, even if they offered me a million dollars.☆what if 要是……，那怎么办？如果……那会怎样？What if the boss walked in here now and saw us?☆as if好像是……She always talks to me as if she was my sister.◇相关练习动词填空：1. If it ______ (be) sunny tomorrow, I ______( walk) to school .2. We ________ (not have ) our sports meeting if theweather ____ (not be ) fine.3. If it _______ (rain ), my father _____ (take ) me to school in his car .4. Tigers _______ (hunt ) for their own food if they _____ (live) in the wild.5. If wolves ________ (be) in the wild, they ______(live) as family groups.6. If we don’t help the wild animals in danger, they ______ (die) soon.单项选择：( ) don’t know if he ______ tomorrow . If he _______, I will tell him about it .A. will come; will comeB. comes ; comesC. comes; will comeD. will come ; comes( ) 2. If Simon ______ hard, he ______ good at English.A. work; isB. works; isC. works; will beD. will work; will be( ) 3. He will come ________ you ask him.A. whetherB. unlessC. ifD. while( ) 4. If the phone _______, can you answer it ?A. ringsB. is ringingC. will ringD. rang( ) 5. Please give me a ring if you _______next Sunday.A. won’t goB. don’t goC. not goD. not to go( ) you know if his school _____a sports meeting next month.A. holdB. holdsC. to ho ldD. will hold( ) are not sure if it ______tomorrow. If i t ______, we won’t climb the South Hill.A. will now, snowsB. will snow, will snowC. snows, snowsD. snows, will snow( ) 8. If we do nothing, there_________ no more giant pandas.A. will haveB. will hasC. will beD. will be going to have( ) 9. There_________ elephants if we don’t protect them.A. won’t be anyB. will have noC. won’t be someD. will be some( ) 10. ---- Do you want to go swimming this afternoon?----Yes, if the weather_________ warm.A. will beB. would beC. wasD. is翻译句子：1． If ___________________(如果明天不下雨的话), we will go to the zoo.2． __________________(如果你生病了), you must see the doctor. 3．You’ll have to have a rest _______________（如果你感到累）4． ___________________(如果我们训练海豚), they perform tricks. 5． Parrots repeat words _______________________ (如果你教他们) 6． _____________(如果老虎住在野外), they will hunt for their own food .7． If you do not hurry up, ________________________________.(你会上学迟到).◇江苏13城市中考试题汇编1. If those wild animals can’t find enough food, they ________ (die) or have to leave their habitat soon. (2010无锡)( ) 2. A tourist will easily lose his way in Beijing ______ he has a map or guide. (2010镇江)A. ifB. becauseC. unlessD. when ( ) 3. ----Excuse me, could you take care of my little dog for me?----________. I ________it if it doesn’t rain after supper. (09镇江)A. Sorry; will walkB. My pleasure; will walkC. I’m sure; walkD. I’m afraid not; walk( ) 4. I have the key to the front door. My parents won’t wait for me if I ___________ back late. (09徐州)A. comeB. will comeC. am coming D have come5. 如果明天下雨，我们就在家做作业。
(2010扬州)_______________________________________________Keys:◇相关练习动词填空：1. is, will walk2. won't have, isn't3. rains, will take4. will hunt, live5. are, will live6. will die单项选择：1~5 D C C A B 6~10 D A C A D翻译句子：1. it doesn't rain tomorrow2. If you are ill3. if you feel tired4. If we train dolphins5. if you teach them6. If tigers live in the wild7. you will be late for school◇江苏13城市中考试题汇编1. will die2. C3. B4. A5. If it rains tomorrow, we will do our homework at home.。