If引导的条件句
If引导的条件状语从句
If引导的条件状语从句一、If引导的条件状语从句的结构If+主语+谓语+其它,主语+谓语+其它.=主语+谓语+其它+if+主语+谓语+其它.注：①有if 的是从句,另一个是主句② if 从句在前有逗号，if从句在后无逗号eg.If he runs, he will arrive there in time .=He will arrive there in time if he runs .如果他跑，她将会准时到达.二、if条件句主句和从句的时态，if译为如果1.主句用一般将来时（will+ V-原），if 从句用一般现在时（be用is/am /are ,实义动词用V-原/V-三单）, 即主将从现注：①当主语为I ,you, we, they ,复数名词，以及由and连接的两个并列成分等时，实义动词用V-原②当主语为he ,she ,it ,that ,单个人名，单数名词等时，用V-三单）eg .If it is (be) rainy , we will stay(stay) at home .If she studies (study ) hard , she will get (get) good grades .2.若主句中含有情态动词(can/may/ must/may/might/should )时，主句为情态动词+ V-原，if从句用一般现在时eg .We can will go(go) out if it stops (stop ) raining .eg.If you want (want) to get good grades ,you should study (study)hard.3.若主句为肯定祈使句或否定祈使句时，if从句用一般现在时注：以V-原开头的句子是肯定祈使句，否定祈使句在V-原前加Don’teg. Eat (eat) them if you are (be) hungry .eg. Don’t go (not go)to play football if she doesn’t finish (not finish)your homework .拓展:if 还可引导宾语从句，译为“是否”If 引导宾语从句时，时态需根据语境确定，如果主句是一般现在时，从句可以根据具体情况选用时态，如果主句是一般过去时，从句必须跟过去时相关( )1.----Mike wants to know if _________ a picnic tomorrow .----- Yes . But if it _________ , We will visit the museum .A. will you have , will rainB. you will have , will rainC. you will have ,rainsD. will you have , rain( )2.We are not sure if it ____ tomorrow .If it ____ , our sports meeting will be put off .A. will rain , rainsB. rains , will rainC. will rain ; will rain ( )3. ---Can you guess if Mike _______ swimming this afternoon ?---I think he will go with us if he _______ fine .A. will go ,isB. will go ,will beC. goes , isD. goes ,will be答案解析：1.迈克想知道是否你们明天将去野营，if译为是否，引导宾语从句，时态根据语境而定，句末有tomorrow , 所以要用将来时。
if引导的条件状语从句
if引导的条件状语从句if条件句：条件句用于陈述语气，表示假设的情况可能发生，其中if 是“如果”的意思。
用法例句①主句为一般将来时态，if从句用一般现在时态（即主将从现）。
We will stay at home if it rains tomorrow.如果明天下雨，我将要呆在家。
②主句中含有情态动词，if从句用一般现在时态。
If you finish your homework, you can go home now. 如果你做完了作业，你现在可以回家了。
③主句为祈使句，if从句用一般现在时态。
Don’t jump into the river if you feel very hot. 如果你感到很热，不要跳入河里。
④主句为过去将来时，if从句用一般过去时态（如果涉及到be动词，一律都用were）。
此时，表达的是和现实相反的推测，用虚拟语气。
If I were you, I wouldn’t do it like that.如果我是你，我就不会那么做的。
If you gave me some money, I would be very happy. 如果你给我一些钱，我就会很高兴的。
构成条件从句主句时态If＋一般现在时主语＋shall/will+动词原形例句If he comes, he will take us to the zoo.1) 用法：(1)条件状语从句通常由连词if引导，意为“如果、假如”，主句不能用be going to表示将来，而应该用shall，will。
If you leave now, you are never going to regret it. (错误)If you leave now, you will never regret it. (正确)(2)if “如果”，引导条件状语从句，主句用一般将来时，从句则用一般现在时，如：If it rains tomorrow, I shan’t climb the hills.(3)另外，主句是祈使句或含有情态动词，从句也用一般现在时。
If引导条件句的用法
If 引导条件句的用法1、真实条件句用于陈述语气,假设的情况可能发生,其中if 是如果的意思;时态关系句型：条件从句主句一般现在时shall/will + 动词原形If he comes, he will bring his violin.典型例题The volleyball match will be put off if it ___.A. will rainB. rainsC. rainedD. is rained答案B;真实条件句主句为将来时,从句用一般现在时;注意：1 在真实条件句中,主句不能用be going to表示将来,该用shall, will.错If you leave now, you are never going to regret it.对If you leave now, you will never regret it.2 表示真理时,主句谓语动词便不用shall will +动词原形,而直接用一般现在时的动词形式;2 非真实条件句1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shouldwould 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 混合条件句主句与从句的动作发生在不同的时间,这时主,从句谓语动词的虚拟语气形式因时间不同而不同,这叫做混合条件句;If you had asked him yesterday, you would know what to do now.从句与过去事实相反,主句与现在事实相反;If it had rained last night 过去, it would be very cold today 现在.4 虚拟条件句的倒装虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略,再把were, should或had 移到从句句首,实行倒装;Were they here now, they could help us.=If they were here now, they could help us.Had you come earlier, you would have met him=If you had come earlier, you would have met him.Should it rain, the crops would be saved.=Were it to rain, the crops would be saved.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,即在从句中be用were代替;If I were you, I would go to look for him.如果我是你,就会去找他;If he were here, everything would be all right.如果他在这儿,一切都会好的;典型例题_____ to do the work, I should do it some other day.A. If were IB. I wereC. Were ID. Was I答案C. 在虚拟条件状语中如果有were, should, had这三个词,通常将if省略,主语提前, 变成were, should, had +主语的形式;但要注意,在虚拟条件状语从句中,省略连词的倒装形式的句首不能用动词的缩略形式;如我们可说Were I not to do., 而不能说Weren’t I to do.5 特殊的虚拟语气词：should1 It is demanded / necessary / a pity + that…结构中的主语从句的谓语动词要用should 加动词原形, should 可省略;句型：1suggestedIt is 2important that…+ should do3 a pity1suggested, ordered, proposed, required, demanded, requested, insisted；+ should do2important, necessary, natural, strangea pity, a shame, no wonder3It is suggested that we should hold a meeting next week.It is necessary that he should come to our meeting tomorrow.2在宾语从句中的应用在表示命令、建议、要求等一类动词后面的从句中;order, suggest, propose, require, demand, request, insist, command, insist + should doI suggest that we should hold a meeting next week.He insisted that he should be sent there.注意：如suggest, insist不表示"建议" 或"坚持要某人做某事时",即它们用于其本意"暗示、表明"、"坚持认为"时,宾语从句用陈述语气;The guard at gate insisted that everybody obey the rules.判断改错:错You pale face suggests that you should be ill.对Your pale face suggests that you are ill.错I insisted that you should be wrong.对I insisted that you were wrong.3在表语从句,同位语从句中的应用在suggestion, proposal, idea, plan, order, advice等名词后面的表语从句、同位语从句中要用虚拟语气,即should+动词原形;My idea is that we should get more people to attend the conference.I make a proposal that we should hold a meeting next week.。
if引导的条件句是什么从句
if引导的条件句是什么从句if 引导的条件句有真实条件句和非真实条件句两种；1、真实条件句：叙述真实可能发生的事情；例句：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。
扩展资料2、非真实条件句：虚拟语气的一种，表示与实际已发生事实相反：例句：If I were you, I would invite him.如果我是你，我会邀请他。
3、另一个常用连词为unless,大多数时候意思与 if not 相近：例句：Let's go out for a walk unless you are too tired.我们出去散步吧，除非你太累了。
例句：If you are not too tired, let's go out for a walk.如果你不太累，我们出去散步吧。
条件状语从句的基本用法1、用if引导：if意为“如果”。
例句：If you cheat in the exam you’ll never get away with it.考试作弊必予追究。
2、用unless引导：unless的意思是“如果不”“除非”。
例句：Unless you go at once you will be late.如果你不马上走，就会迟到的'。
3、用as [so] long as引导：as [so] long as的意思是“如果”“只要”。
例句：I’ll remember that day as long as I live.只要我活着，我就不会忘记那个日子。
4、用in case引导：in case用连词引导条件状语从句时，其意为“如果”“万一”。
例句：In case I forget, please remind me about it.万一我忘记，请提醒我一下。
5、条件状语从句的时态：当主句为将来时态或含有将来意义时，条件状语从句习惯上要用一般现在时表示将来意义，而不能直接使用将来时态。
if引导的条件状语从句总结(精)
if引导的条件状语从句总结(精)if引导的四种条件状语从句一、零条件句/绝对真实条件句(Zero Conditional)零条件句，又叫绝对真实条件句，用于阐述事实。
用来表达在该条件下，结果一定会如此(如规则，客观规律、真理等)。
结构是：If+主语+do/does，主语+do/does。
其从句和主句的谓语动词通常为一般现在时。
二、第一条件句/相对真实条件句(First Conditional)第一条件句又叫相对真实条件句，谈论将来可能发生的事情，并考虑这件事情的结果。
强调偶然性或一次性的条件，也可以与绝对真实条件句同义。
if从句用一般现在时或其他现在时，表示将来可能发生的事情(条件);主句用一般将来时，表示这件事情的结果。
结构是：If+主语+do/does，主语+will do。
三、第二条件句/现在虚拟条件句(Second Conditional)第二条件句是虚拟条件句的一种，即现在虚拟条件句(Unreal Present)，用来表达在现在或将来时间下不太可能或不可能发生的条件，这种条件句还可以用来表示试探性的、委婉的语气(可以理解为不大有自信，所以不太真实的条件)。
结构是：①与将来事实相反的非真实条件句是If+主语+should do/were to do/did，主语+would/should/could/might do;②与现在事实相反的非真实条件句是If+主语+did，主语+would/should/could/might+do。
四、第三条件句/过去虚拟条件句(Third Conditional) 第三条件句是表示与过去事实相反的虚拟语气，是用来表达如果(If)当时那样发生，另外一方面(当时)结果会如何。
通常是指过去的事情，带有一切已经太迟而不能够补救的意思。
结构是：If+主语+had done，主语+would/should/could/ might+have done。
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.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.4.if从句用一般现在时，主句用一般现在时5.if从句用现在进行时，主句用一般将来时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.。
if引导的条件句
tired
A:What will you do if you are tired? B: I will… if I am tired.
go to bed/have a rest/listen to music...
Discuss with your partner:
What will you do if you have a lot of money one day?
What’s the rule? （3）
if条件状语从句中，如果主句 是祈使句，从句用一般现在时。
•Let me know if he comes. •Don’t wait for me if I am late. •Put up your hands if you have any questions.
What’s the rule? （2）
if条件状语从句中，如果主句 有must，can，may等情态动 词，从句用一般现在时。
•You must stop if the traffic light is red. •You may go fishing if you are free.
•He can go home if he finishes his homework.
Find the rule (2)
I will take part in the English competition.
Find the rule (2)
Dad will buy a pen for me.
Dad will buy a pen for me. I will take part in the English competition.
What’s the rule? （1）
用if引导的条件状语从句15个
用if引导的条件状语从句15个如果引导的条件状语从句是英语语法中非常常见的句型，用于表达某种条件下发生的情况。
下面将介绍15个以if引导的条件状语从句的相关内容。
1. **Zero Conditional**Zero conditional用于表达普遍真理或习惯性的动作，结构为if + 现在时，现在时。
例如：If you heat water to 100 degrees, it boils.2. **First Conditional**First conditional用于表达将来可能发生的事情，结构为if + 现在时，将来时。
例如：If it rains tomorrow, we will stay indoors.3. **Second Conditional**Second conditional用于表达与现在事实相反的假设，结构为if + 过去时，would/could/might + 原形动词。
例如：If I were rich, I would travel around the world.4. **Third Conditional**Third conditional用于表达与过去事实相反的假设，结构为if + 过去完成时，would/could/might + have + 过去分词。
例如：If I had studied harder, I would have passed the exam.5. **Mixed Conditional**Mixed conditional结合了第二和第三条件句的结构，用于表达过去的假设对现在的影响，或现在的假设对过去的影响。
例如：If I had known you were coming, I would have baked a cake.6. **Unless**Unless的意思是“除非”，引导的条件状语从句表示否定条件。
结构为unless + 句子，相当于if not。
人教版中考英语语法知识点If+引导的条件句+练习
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。
if引导的条件状语从句讲解
条件状语从句在句子中做条件状语的从句称为条件状语从句。
通常置于句首或句尾。
一．条件状语从句通常由if（）, unless（），as long as（）引导。
例如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？尝试一下：（补全句子）If it rains tomorrow, we won’t go to the park.______________________________________。
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。
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.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. =_________________________________________.Hurry up, or you’ll be late. =__________________________________________________..考题(2010重庆中考)Work hard，________ you may catch up with your classmates soon.A.orB.butC.andD.yet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……”。
if引导的条件句三种情况
1•对现在虚拟：条件句：一般过去时主句：could/would/+动词原形。
2•对过去虚拟：条件句：过去完成时主句：could/would have done0 3•对将来虚拟:条件句：l.were to do ;2.should do ; 3•—般过去时：主句could/would/+动词原形。
—、对现在情况的虚拟条件从句中谓语动词用一般过去式,主句用,f would/should/might/could+动词原形”形式,表示对现在不可能实现情况的假想。
If I were you,I would choose to work in a small town.如果我是你f我会选择在小城镇工作。
（事实上我不是你）If I had a map now,we could easily get out of the forest.如果现在有地图，我们能很容易地走出森林。
（事实上是现在没有地图）注意：在条件从句中，如果谓语动词是be的形式，不管主语是单数还是复数，书面语中用we©而口语中如果是单数,也可以用was,不过在if I were…中一般用were.If the world were perfect,how could we enjoy the pleasure and comfort of being successful?世界若完美,我们如何能尝到创造成功的快慰?二、对过去情况的虚拟条件从句中谓语动词用过去完成式,主语用,/would/could/should/might+have+动词的过去分词"形式。
If it had not been for your help yesterday^ could not have caught the bus.如］果昨天没有你的帮助，我不会赶上公交车。
（事实是你昨天已经帮助了我，所以我赶上了车）三、对将来情况的虚拟在表示与将来事实相反的条件从句中,谓语动词可用should do,were to do或动词的过去式三种形式表示，但意义略有不同。
If条件句
3.与过去事实相反的虚拟条件句 构成 条件状语从句 主句
If + 主语 + 动词过去完成 主语+ would, should, could, might+ have + 式 过去分词
例如 If there had been no air in the tube, the result would have been better.
某英文网站正在开展关于“高一是否该分文理科”的讨论。 请你根据下面所给的要点提示，用英语写一篇短文， 描述目前存在的两种看法，并陈述你的观点，以便向该网 站投稿。 赞成分科的人认为1. 可集中精力学习；2. 减轻学习压力； 3. 学自己喜欢的学科。 反对分科的人认为1. 学科知识受限制；2. 影响个人素质提 高； 3. 对科目缺乏深入了解。你的观点…… 注意：1．词数：120词左右； 2．参考词汇： 素质：quality n. 分科：division n. 全面的：all-round adj. 3. 短文的开头已给出，不计入词数。
I.虚拟语气用在条件状语从句中 虚拟语气用在条件状语从句中，通常从句由连词if 引导。 1.与现在事实相反的虚拟条件句 条件状语从句 If +主语 +动词过去 式(be的过去式用 were) 主句 主语+ would, should, could, might+动词原形
例 If I feared death, I wouldn’t be a Party member. 怕死就不做共产党员。 If there were no air, we couldn’t live. 如果没有空气，我们就不能生活。
if 引导的条件句 if引导的条件句表示在某种条件下，会导致另 一事发生。句式为if从句+ 主句。 中文意思是“如果某事发生（或不发生）， 另一事就（不）发生”。通常分以下两种情形： 一、真实条件句 二、虚拟条件句
if引导的条件状语从句的用法
（3）假设
真的，或者有可能成为真的；
（二）假设将来，假设的条
将来
件是将来可能实现的。
1. if 非真实条件句（虚拟）——假设现在
（二）遵循的原则
should do
might+do
例 7 If I _____(be) a bird,I would fly to you right
状态，是正在玩球的意思，
所以此空填 is playing。
3. if 引导的真实条件状语从句——假设将来
例 3 If it _____(rain) tomorrow,we will stay at home.
解析：如果你不想受伤，
就不要玩刀。根据 Don’
t
play with the knife,主句是祈使句，所以从句为 if 引导
to the park.
he will take me to the park,主句用的一般将来时，而且
可以分析出，他哥哥现在还没有回，所以从句为 if 引
导的表将来的条件状语从句。根据“主将从现”的原
则，此空填 comes。
2. if 非真实条件句（虚拟）——假设过去
例8
Years ago if someone_____ (turn) round to
批改学生作文时，遇到拼写错误较多的学生可以这样
及各个时代相关代表作品的赏析，感受中西方文化的
评价：
不同，提高其审美水平；在进行人教版（2014）高中英
neat and tidy！
学生参观学校的科学实验室或者本地的科技馆，感受
1. 认 同 欣 赏:I like your handwriting，which is so
if条件句
if 引导的条件状语从句条件状语从句是在复合句中作条件状语的句子。
表示假如有从句的动作发生就会有主句的动作发生。
条件状语从句常由连词if引导。
(一)连接词ifif如果，是引导条件状语从句的连接词，表示主句中动作发生的条件。
☞If you get up early, you will catch the bus. 如果你早起的话，就能赶上那班公共汽车。
☞You must see the doctor if you are ill. 如果你生病了，就必须去看医生。
(二)if引导的条件状语从句的构成构成方式为＂主句+if引导的条件状语从句＂或＂if引导的条件状语从句+主句＂。
☞I will go to his birthday party if he invites me.=If he invites me, I will go to his birthday party. 如果他邀请我，我会去参加他的生日聚会。
(三)if引导的条件状语从句的时态在一般情况下，如果主句表示将来的意义，从句用一般现在时表将来。
常见的有以下几种：1. 主句谓语中有will, shall, won’t 表示将来时，从句用一般现在时。
☞You will be late for school if you get up late. 如果你起晚了，上学将会迟到。
☞If it rains tomorrow, we won’t go to the Great Wall. 如果明天下雨，我们就不去长城。
2.主句中含有can, may, must等情态动词时，从句用一般现在时。
☞If I finish my homework, I can watch TV. 如果我完成了家庭作业，就可以看电视。
3.主句是祈使句，从句用一般现在时。
☞Don’t forget to lock the door if you are the last one to leave. 如果你最后一个离开，别忘了锁门。
if引导的条件句的用法
1．if引导的条件句的用法1)当if用于表示普遍真理和科学事实的条件句中，其主从句的谓语动词一般都用一般现在时。
①If you heat ice, it melts.如果给冰加热，冰便融化了。
②If you pour oil on water, it floats.把油倒在水上，油浮于水面。
③If the temperature drops to zero degrees centigrade, water freezes.如果温度降至零度，水便结冰了。
④If you divide eight by two, you get four.8除以2，等于4。
2)当if用于表示现在习惯动作条件句中，其主从句的谓语也都用一般现在时。
①lf I make a promise, I keep it.我只要许下诺言，就信守不渝。
②if it rains, I go to work by bus.每逢雨天，我就搭乘公共汽车上班。
3)当if用于表示过去习惯动作的条件句中，其主从句谓语动词都用一般过去式。
①lf I made promise, I kept it.以前我只要许下诺言，就总是信守不渝。
②If it rained, I went to work by bus.以前每逢下雨，我就坐公共汽车上班。
4)if还常与从句一般现在时，主句用 will/shall/can加动词原形结构搭配使用。
①If you go to England, you will have to learn English .如果你到英国去，就必须学英语。
②If it is fine tomorrow , we can have a picnic somewhere .如果明天晴天，我们可以去野餐。
5)if从句还常出现以下结构，主句祈使句，从句一般现在时。
①If you wake up before me, give me a call.如果你比我醒得早，就叫醒我。
if引导的条件句
1. if引导的条件句（1）if引导的条件句if引导的条件状语从句中if 意为"如果"，有以下两种基本句型：A. If…,…will (not)…. /…will (not)…if…. (此时逗号不可省略)基本含义：表示假如有从句的动作发生,就会或不会有主句的动作发生。
例如：If it rains tomorrow, I'll go to school by bus. / I'll go to school by bus if it rains tomorrow.If it rains tomorrow, they won't go outside to play./ They won't go outside to play if it rains tomorrow.注意时态：主将从现B. If…,…may (might)…./…may（might）…if….基本含义：表示假如有从句的动作发生，就"可能会"有主句的动作发生。
即主句动作发生的肯定程度达不到will的程度。
例：If you go to bed too late, you might feel tired tomorrow. /You might feel tired tomorrow if you go to bed too late.注意时态:紧跟if的从句仍需用一般现在时。
表普遍现象或客观真理以及习惯动作，或重复发生，预示要发生，则主从均为现在时。
从句用一般现在时，主句用should/must1. If he hard, he will get good grades.A. studyB. studiesC. will studyD. studied2. I want to know if Mary to the party tomorrow.A. goB. wentC. will goD. goes3. Everyone must dress up. If you , they won’t let you in.A. don’tB. won’tC. can’tD. mustn’t4. Mary will go to Sanya if she a five-day trip.A. haveB. hadC. will haveD. has5. If he comes late, he will miss the train.A. andB. soC. /D. or。
if 引导的条件句
if 引导的条件句if引导的条件句表示在某种条件下，会导致另一事发生。
句式为if + 从句，主句。
中文意思是“如果某事发生（或不发生），另一事就（不）发生”。
通常分以下两种情形：一、真实条件句1. if从句和主句都用一般现在时，表示客观真理或习惯和持续发生的事情。
如：If the moon goes near the earth, the tide goes high. 如果月亮离地球距离近，潮水就高。
2. if从句用一般现在时，主句用一般将来时，表示从句中的动作如果发生，那么主句中的动作也将发生。
如：If it stops raining later this afternoon, we will eat out. 如果今天下午晚些时候雨能停，我们就出去吃饭。
3. if从句用一般现在时，主句用祈使句，表示给某人提建议或命令某人做某事，及提出建议或请求。
如：If you are not likely to be in town, please let me know. 如果你不可能在城里，请让我知道。
二、虚拟条件句虚拟条件句，也称非真实条件句，表示在某种假想的条件下，将导致某事发生。
从句中所陈述的事情仅仅只是说话者的想法，不是事实，也不可能发生。
1. if从句用一般过去时（did / were），主句用would / could / should / might + do，表示现在不可能发生的事情，if 从句中所陈述的事情与现在的事实相反。
如：If I were Liu Xiang, I would train hard for the 2008 Olympic Games.如果我是刘翔，我会为了2008年奥运会努力训练。
2. if从句用一般过去时（did / were或were to + do），主句用would / could / should / might + do。
表示将来不可能发生的事情，if 从句中所陈述的事情与将来的事实相反。
if从句的三种用法
千里之行，始于足下。
if从句的三种用法if从句是英语语法中常见的一个句子结构，用于表示假设、条件或可能性。
依据具体的语境和意义，if从句有三种常见的用法：条件句、假设句和虚拟语气句。
下面将具体介绍这三种用法。
一、条件句（Conditional Sentences）条件句用于表示某种条件下的结果或后果。
它由if引导，分为三种类型：零条件句、一般条件句和虚拟条件句。
1. 零条件句（Zero Conditional Sentences）零条件句表示事实真实的条件和结果，表示的是普遍真理或状况。
它的结构通常是：if + 现在时，现在时。
例如：- If you heat ice, it melts.（假如加热冰，它会溶化。
）- If it rains, the ground gets wet.（假如下雨，地面会变湿。
）2. 一般条件句（First Conditional Sentences）一般条件句表示可能发生的条件和结果，表示的是将来可能发生的状况。
它的结构通常是：if + 现在时，将来时。
例如：- If it rains, I will stay at home.（假如下雨，我会呆在家里。
）3. 虚拟条件句（Second Conditional Sentences）虚拟条件句表示不太可能实现的条件和结果，表示的是与现实相反的状况。
它的结构通常是：if + 过去时，would + 动词原形。
第1页/共3页锲而不舍，金石可镂。
例如：- If I had a lot of money, I would travel around the world.（假如我有很多钱，我会环游世界。
）二、假设句（Suppositional Sentences）假设句用于表示假设、猜想或非真实状况。
它由if引导，通常是对将来可能的状况进行推想或假设。
1. 假如假设是可能的（Possible Condition）这种状况下，if从句和主句中的动词形式一般都使用现在时。
if来引导的句子
"if" 是英语中的一个条件状语从句的引导词，它通常用来表示某个条件下的结果或假设。
以下是一些使用 "if" 引导的句子示例： 1. "If you study hard, you will pass the exam." (如果你努力学习，你会通过考试。
)
2. "If it rains tomorrow, we will stay at home." (如果明天下雨，我们会呆在家里。
)
3. "If the car breaks down, we will have to walk." (如果车坏了，我们只能走路。
)
4. "If I had more time, I would finish the project." (如果我有更多的时间，我会完成这个项目。
)
5. "If you want to succeed, you must work hard." (如果你想成功，你必须努力工作。
)
请注意，"if" 引导的从句通常放在主句之后，并且使用逗号与主句分隔。
例如：
"I will go to the party if my friend is going too." (如果我的朋友也去，我会去参加派对。
)。
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16.The foreign friend speaks Chinese so well as if he ___ a Chinese. A. is B. was C. should be D. were
.—If he ___, he___ that food. —Luckily he was sent to the hospital immediately. A.was warned; would not take B.would be warned; had not taken C.had been warned;would not have taken D.would have been warned; had not taken
对过去的虚拟
ቤተ መጻሕፍቲ ባይዱ
If you had taken my advice, you would not have made such a mistake. If I hadn’t lived among the peasants for five years, I shouldn’t have been able to write such good novels. If he had been sent to a better hospital, the man’s life might have been saved. If I had been more careful, I could have done better.
1.If you ___ (arrive) ten minutes earlier, you could have seen them off. 2.If they___ (not help) us ,our experiment would have failed. 3. ___ I not ___ (forget) his telephone number, I would have rung him. 4.He is busy now. If he ___ (be) free, he___ (go) with you.
15.If you ___ that late movie last night, you wouldn‘t be so sleepy. A.haven‘t watched B.hadn‘t watched C.didn‘t watch D.wouldn't have watched
8.He didn't take his parents' advice and he is not a college student now. If he ___ ___ his parents' advice, he ___ ___ a college student now.
If 引导的条件句
Reading One
If her friends are popular, then Joy may enjoy high status at school. If Joy has some information to share about a popular girl at school, this proves that she has a friendship with this girl. If a woman tells her husband about a problem, she will expect him to listen and offer sympathy.
5.The manager was in his office then. If he ___ (be) here, everything ___ (settle) in a minute.
6.Lucy didn't come to class today because she didn't feel well. ___ she ___ well, she ___ ___ ___ to class today. 7.I don't know French, so I can't talk to the French friends. If I ___French, I could talk to the French friends.
对将来的虚拟
If I were to/should do it ,I would do it in a different way. If this were to happen again , we wouldn’t let you off so easily. If they should dare to invade our country , we would wipe them out completely.
非真实条件句
If I become president, I’ll make all of my people live a happy life. If I were you, I would read it again. 如果我是你的话，我再读一遍。（事实上 我不是你） What would I do if I were in your place? 要是我处于你地位我会怎么办？（事实上 我不在你的位置上）
省略If的非真实条件句
Were I you, I would not let out the secret. Had we made fuller preparation, we should have won the game. Had you taken my advice, you wouldn't have been late for the meeting. Should she come, I would tell her the secret.
A.Was I B.Were I C.If I am D.If I had been
14.If you had spoken clearly, you would___.
A.understand it B.have understood C.be understood D.have been understood
Once (upon a time) there was a true love at my hand, but I didn't cherish it. I hadn't felt regretful until it was gone. There is nothing more miserable than it. If God were to give me another chance to restart, I would express my love to that girl. If I had to add a deadline to the love, it would be ten thousand years, I hope. If God should give me another chance to restart, I would express my love to that girl.
一
If you divide eight by two, you get four. If the temperature drops to zero degree centigrade, water freezes. If I make a promise, I keep it.
二
A. will catch B. would catch C. would have caught D. will have caught
省略句
4.Had he studied hard, he___ the exam.
A. would pass B. could pass C. had passed D. would have passed
省略整个条件句
Such mistakes could have been avoided. (省 略了if we had been more careful). 这样的错误本来是能够避免的。 I should have caught the train. (省略了if I had left a little earlier)
对现在的虚拟
If I were your father, I would criticize you more severely. How nice it would be if you could stay a bit longer！ If he were here ,he might be able to help.
8. ___ what was going to happen ,I would never have left her alone. A.Had I known B.If I know C.If I knew D.If had I known
11. ___ in your position, I would help him.
If he will accept the nomination, a lot of electors will vote for him. If you will wait for a few more minutes, the doctor will see you without your making an appointment.