虚拟语气if假设句
虚拟语气if的三种用法教案-定义说明解析
虚拟语气if的三种用法教案-范文模板及概述示例1:标题：虚拟语气if的三种用法教案引言：虚拟语气if是英语语法中的一个重要概念。
它用于描述虚拟的情况或假设，与实际情况相反或不可能实现的情况。
在本文中，我们将介绍虚拟语气if的三种常见用法，并提供相关教学案例。
一、虚拟语气if表示对过去情况的假设1. 如果现在完成时表示过去的假设例如：If I had studied harder, I would have passed the exam.（如果我当时更努力学习，我就能通过考试。
）2. 如果过去完成时表示过去情况的假设例如：If you had told me earlier, I would have helped you.（如果你早点告诉我，我就会帮助你。
）教学案例：让学生完成以下句子，使用虚拟语气if表示对过去情况的假设：1. 如果他没有错过公交车，他就不会迟到了。
2. 如果我看到那本书，我就会告诉你。
3. 如果我知道你的生日，我就会为你准备礼物。
二、虚拟语气if表示对现在情况的假设1. 如果一种不可能实现的现实情况例如：If I were a bird, I would fly around the world.（如果我是一只鸟，我就会飞遍全世界。
）2. 如果一种与实际情况相反的情况例如：If it wasn't raining, we would go for a walk.（如果不下雨，我们就会去散步。
）教学案例：让学生完成以下句子，使用虚拟语气if表示对现在情况的假设：1. 如果我有超能力，我会帮助所有需要帮助的人。
2. 如果我有时间，我会去旅行。
3. 如果我不生病，我就会参加派对。
三、虚拟语气if表示对将来情况的假设1. 如果将来某种情况不会发生例如：If it doesn't rain tomorrow, we will have a picnic.（如果明天不下雨，我们将去野餐。
if的虚拟语气的用法例句
if的虚拟语气的用法例句一、if的虚拟语气简介虚拟语气是英语中一种特殊的语法现象，常用于表示假设情况、与实际情况相反的条件或无法实现的愿望等。
if引导的条件句中，根据其所表示的条件类型和时间性质，使用不同形式的虚拟语气。
二、与现在事实相反的虚拟语气1. 假设条件：如果+动词过去式（be动词用were）例句：If I were a bird, I would fly high in the sky.2. 假设条件：如果+动词过去完成时（had + 过去分词）例句：If he had studied harder, he would have passed the exam.三、与现在事实相反但可能实现的虚拟语气1. 假设条件：如果+动词过去式（be动词用were）结果：主将从现例句：If it rained tomorrow, I would stay at home.2. 假设条件：如果+动词过去完成时（had + 过去分词）结果：主将从现完成例句：If he had invited me, I would have gone to the party.四、与过去事实相反的虚拟语气1. 假设条件：如果+主语+had + 动词过去分词结果：主语+would/could/might + have + 过去分词例句：If I had known the truth, I would have made a different decision.2. 假设条件：如果+主语+had not +过去分词形式，结果也用一般过去时态例句：If we hadn't missed the train, we would have arrived on time.五、与将来事实相反的虚拟语气1. 假设条件：如果+动词过去式（be动词用were）结果：主将从现（应该+动词原形）例句：If they were here, they would help us.2. 假设条件：如果+should/were to/might/could/would + 动词原形结果：主将从现（应该+动词原形）例句：If he should call, please ask him to wait.六、虚拟语气中常用的连词和引导短语1. if: 引导条件状语从句，表示假设情况。
if would 虚拟语气例句
if would虚拟语气例句虚拟语气是英语语法中一个重要的概念，用来表示与事实相反或假设的情况。
在英语中，虚拟语气的运用非常广泛，可用于表达假设、建议、愿望、要求等等。
掌握好虚拟语气的用法，有助于提升我们的英语表达能力。
下面是一些关于虚拟语气的例句，希望能对大家有所帮助：1.If I were you,I would study harder.（假设句）如果我是你，我会更努力地学习。
2.I wish I could fly like a bird.（愿望句）我希望我能像鸟一样飞翔。
3.If I had more time,I would go traveling.（假设句）如果我有更多时间，我会去旅行。
4.She suggested that he attend the meeting.（建议句）她建议他参加会议。
5.If she had arrived earlier,she wouldn't have missed the train.（假设句）如果她早点到，她就不会错过火车了。
6.They demanded that he apologize for his behavior.（要求句）他们要求他为自己的行为道歉。
7.If I won a million dollars,I would donate it to charity.（假设句）如果我赢得一百万美元，我会把它捐给慈善机构。
8.He acted as if he knew everything.（假设句）他表现得好像他什么都知道。
9.If I had known about the party,I would have gone.（假设句）如果我早知道有派对，我就会去的。
10.It's about time you finished your homework.（建议句）你应该早点完成作业了。
以上是一些关于虚拟语气的例句，通过阅读和学习这些例句，我们可以更好地理解虚拟语气的用法，并能够在实际应用中灵活运用。
If 引导的虚拟语气
If 引导的虚拟语气虚拟语气是一种特殊的动词形式，用来表示说话人所说的并不是事实，而是一种假设，愿望，怀疑或推测。
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能使用虚拟语气。
通过句子的意思，看假设的条件是否能够实现，能够实现的是真实条件句，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。
判断这个假设是与那个事实相反，通常有三种情况1与过去事实相反2与现在事实相反3与将来事实相反最基本的虚拟语气句型1虚拟现在时表示与现在事实相反的假设，其if从句的谓语形式用动词的过去式(be一般用were)，主句用would/should/could/might+动词原形。
例句:If I place were alike ,there would be little need for geographers.如果各个地方都一样，就读需要地理学家了。
If I were you,I should do that.如果我是你，我就那么做。
2虚拟过去时是表示与过去事实相反的假设，if从句的谓语形式用过去完成时，即had+过去分词。
主句用would/should/could/might+have+过去分词。
例句：If he had know your address yesterday,he would have telephoned you如果昨天他知道你的地址，那他就打给你了。
If he had been there last night,it wouldn’thave happened.如果他昨晚在那里，这事就不会发生。
If you had come a little earlier,you could have met him.如果你早点来，你就能遇见他。
3虚拟将来时是表示对将来实现的可能性很小或不确定的假设。
If从句的谓语形式用一般过去式或用were to/`should+动词原形，主句用would/should/could/might+动词原形。
if在条件状语从句中的用法归纳
if在条件状语从句中的用法归纳下面是小编整理的一些关于if 在条件状语从句中的用法，希望对大家有帮助。
if是英语中的一个常见词汇,可用作连词和名词,用法多变,意义多样。
无论在口语还是书面语中都是一个常用词,用法灵活,词意多样,需要我们在平时的学习和使用中用心把握if 在条件状语从句中的用法归纳虚拟语气用来表示说话人所说的话并不是事实，而是一种假设、愿望、怀疑或推测。
if 条件状语从句中虚拟语气的判断：if 条件状语从句有真实条件句和非真实条件句。
假设条件是可以实现的句子为真实条件句，反之为非真实条件句，要用虚拟语气。
其形式分为以下三种：(1) 与过去事实相反的假设。
结构为：从句的谓语动词用“had + 过去分词”，主句用“should (would, could, might) + have + 过去分词”。
If it had not rained so hard yesterday, we could have played tennis.如果昨天没有下大雨，我们就能玩网球了。
(2) 与现在事实相反的假设。
结构为：从句的谓语动词用过去式，系动词用were，主句的谓语用“should (would, could, might) + 动词原形”。
If I were in your position, I would marry her.如果我是你，我就娶她为妻。
(3) 与将来事实相反的假设。
结构为：从句的谓语动词用“should (were to) + 动词原形”，主句用“shou ld(would, could, might) + 动词原形”。
If you should miss the chance, you would feel sorry for it.如果你错过了这次机会，你会难过的。
if和will的用法虚拟语气
if和will的用法虚拟语气一、if和will的用法概述if和will都是英语中常用的虚拟语气形式，用来表示与实际情况相反或假设的情况。
它们有着各自独特的用法和含义，在句子中起到不同的作用。
二、if引导条件句时的用法1. 表示可能性如果真实情况下可能发生某事，可以使用if引导条件从句。
例如：If it rains tomorrow, we will stay at home.（如果明天下雨，我们就会呆在家里。
）这个句子表示，如果明天下雨这种可能性存在，那么我们将选择待在家里。
2. 表示假设当前提是无法满足或纯粹是个假设时，可以使用if引导条件从句。
例如：If I were you, I would study harder.（如果我是你，我会更加努力学习。
）在这个例子中，“我是你”这个前提显然是不可能实现的，所以我们使用了“were”而不是“was”。
3. 表示建议通过一个假设来为对方提出建议或提供帮助时，可以使用if引导条件从句。
例如：If you need any assistance, feel free to ask me for help.(如果你需要任何帮助，请随时向我寻求。
)在这个句子里，“如果你需要任何帮助”是一个假设条件，用来表示作者愿意提供帮助。
三、will引导虚拟条件句时的用法1. 表示说话人的意愿或意图当说话人通过虚拟语气表达自己对某事的意愿或意图时，可以使用will引导后面的从句。
例如：She asked me if I would help her with the project.(她问我是否愿意帮她完成这个项目。
)在这个例子中，“我愿意帮忙”正好符合了will的用法，表达出了说话人对于帮助的意愿。
2. 表示猜测或推测在一些情况下，使用will来表示根据某种迹象或判断得出某种猜测或推测。
例如：If he doesn't hurry up, he will miss the train.(如果他不赶紧，他会错过火车。
英语中-if从句中的虚拟语气用法-经常用到的知识点！
英语中-if从句中的虚拟语气用法-经常用到的知识点！每天坚持一点点，每天进步一点点。
1.If + were/did (动词的过去式)，主语+would/might/should/could+do…用法该句型常用于表示对现在的情况的假设。
1)If I were you, I would not be so proud.如果我是你，我不会如此自负。
2)I don't have a cellphone. If I had one, it would be convenient for me to get in touch with others.我没有手机，如果有的话，和别人联系就方便多了。
3)If I were in your position, I would think better of it.如果我处在你的位置，我会重新考虑的。
2.If +had done, 主语+would/might/should/could + have done…该句型用于表示对过去或已经发生事情的虚拟假设。
1)What a pity it is that you didn't attend the concert yesterday! If you had attended the concert, you would have seen the famous singer.真遗憾昨天你没有去听音乐会！如果你去了，就能见到那位著名歌手了。
2)Anyone in this position would have done the same. If anyone had been in his position, he would have done the same. 任何处在他位置的人都会这样做的。
3.If + were/did/were to do/ should do, 主语+ would/might/should/could +do…该句型常用于表示对将来的假设。
if引导的条件句中的虚拟语气
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 tim e , 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 w ould 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 his 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。
if条件句
if条件句
if条件句是一类英语句型，用于表达条件和假设。
其基本结构为
“If + 条件句子，主句”。
其中，条件句子通常采用现在时、过去时或虚拟语气的形式，主句则是表示结果的句子。
if条件句通常分为四种类型：
1.真实条件句（Real Conditional Sentences）：表示可能发生的情况，条件句子使用现在时态，主句使用将来时态。
例句：If it rains tomorrow, I will stay at home.
如果明天下雨，我会呆在家里。
2.虚拟条件句（Unreal Conditional Sentences）：表示假设或不可能实现的情况，条件句子使用虚拟语气，主句使用过去时态。
例句：If I had a million dollars, I would buy a house in the countryside.
如果我有一百万美元，我会在郊区买房子。
3.第二种虚拟条件句（Second Conditional Sentences）：表示目前不可能实现的情况，条件句子使用虚拟语气，主句使用现在时态。
例句：If I were you, I would quit that job.
如果我是你，我会辞掉那份工作。
4.混合虚拟条件句（Mixed Conditional Sentences）：表示对过去的事情进行虚拟推论，条件句子使用过去时态，主句使用现在完成时态。
例句：If he had studied harder, he would have passed the exam.
如果他学得更努力些，他就能通过考试了。
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。
关于英语中虚拟语气的用法介绍
If you had taken my advice, you wouldn’t(couldn’t) have failed in the exam.如 果你听了我的建议，你就不会考试不及格。（事实上你根本没听我的。）
3 表示与将来事实可能相反的假设和结果。如： If it should rain, the crops would(could, might)be saved.假如天下雨，庄稼可能就
4.用于特定词语后的宾、主、表及同位语从句中 虚拟语气用于表示要求、建议、命令等意义的动词、名词及形容词后的宾语从句、 主语从句、表语从句及同位语从句中。其形式都是“sould+动词原形”，should 可省略。
1）用于宾语从句中 常用的动词： ask,advise,command,decide,demand,insist,order,propose,request,require ,suggest 等。 He insisted that we all(should) be in his office at six. The doctor suggested that she (should) take a trip. 2)用于主语从句中 常用的结构：It is+形容词或过去分词+主语从句（用虚拟语气） 常见的形容词或分词： essential,urgent,necessary,important,advisable,natural,desired,demand ed,ordered,required,suggested 等。 It is necessary that this machine(should) be oiled every day. It is required that the machine be tested. 3)用于表语从句或同位语从句中 常用的名词： advice,command,demand,desire,idea,order,proposal,request requirement 等。 His suggestion is that we go out on a picnic next Sunday.(表语从句） His suggestion that we go out on a picnic next Sunday is wonderful.( 同位语从句)
虚拟语气在条件状语从句中用法if条件句
虚拟语气
Exercises
1. Alan ___ the party if he had gone to London.
2. A. would have missed B. had missed
3. C. would miss
D. missed
4. 2. If I knew you were coming, I ___ you at the airport.
She was honoured by people all over the world,
Because She was an inventor and a scientist .
Because She was given the
Nobel Prize for Chemistry in
1911 .
• If I were a designer , I would design a spaceship .
• If I were clever enough , I would have designed a spaceship.
• If I were an astronaut , I would travel into space.
虚拟语气
6. Simon looks as though he never ___ a square meal(吃得饱), though his parents feed him very well. A. get B. getting C. got D. should get
7. He is talking so much about America as if he ___ there. A. had been B. were C. was D. been
if引导的条件问句与虚拟语气
I wish he would answer my letter.
I wish prices would come down.
I wish you would help me.
I wish you would stop asking silly questions.
4. 省略if 采用倒装语序的条件句。有时可以把含有助动词、情态动词、be或have的虚拟条件句中的连词if省去，而将had , should, were 等词提到主语之前，即用倒装结构。If he had worked harder, he would have got through the exams.==>Had he worked harder, he would have got through the exams.If he were to leave today, he would get there by Friday.==>Were he to leave today, he would get there by Friday.If I were in your place, I wouldn’t do that.==>Were I in your place, I wouldn’t do that.
II: 虚拟语气在从句中用should的情况:
1. 在表示建议,要求,命令,想法的动词后的从句里, 用should + 动词原形, should 可以省略. 如 advise, agree, command, decide, demand, determine, grant, indicate, insist, order, prefer, propose, request, require, stipulate, suggest, urge, vote.常考到的是: suggest, advise, demand, require, propose, insist, order, request.
英语假设句子怎么表达
英语假设句⼦怎么表达1. 英语中的假设句是怎么回事1. 虚拟语⽓⽤来表⽰假想，⽽不表⽰客观存在的事实，所说的是⼀个条件，不⼀定是事实，或与事实相反。
虚拟语⽓通过谓语动词的特殊形式来表⽰。
英语中的语⽓分为陈述语⽓、祈使语⽓、虚拟语⽓三类。
虚拟语⽓表⽰说话者所说的话并⾮事实，或难以实现的，甚⾄表达相反的概念。
另外表⽰主观愿望或表达某种强烈的感情时，也⽤虚拟语⽓。
2. 虚拟语⽓表⽰说话⼈的主观愿望、猜疑、建议或与事实不符的假设等，⽽不表⽰客观存在的事实。
虚拟语⽓是由句中的谓语从句的特殊形式表⽰出来的。
如：If I were a bird,I would be able to fly in the air.如果我是⼀只⼩鸟，我就能在空中飞⾏。
I wish I could pass the examination.我希望我能通过考试。
May you succeed!祝你成功！If only we had been college students last year!上⼀年我们要是⼤学⽣该多好！3. 应⽤条件在表⽰假想的虚假的、与事实相反的或难以实现的情况时⽤虚拟语⽓，表⽰主观愿望或某种强烈情感时，也⽤虚拟语⽓。
即当⼀个⼈说话时欲强调其所说的话是基于⾃⼰的主观想法，愿望，假想，猜测，怀疑或建议，⽽不是根据客观实际，就⽤虚拟语⽓。
主要是英语语法的⼀种表达。
.4. from 度娘百科，更多请⾃⾏度娘.2. 英语中假设有⼏类英语中表⽰假设的句⼦主要是虚拟语⽓，其表⽰⽅式有：1.以if条件从句为虚拟语⽓标志：与现在事实相反从句时态⽤⼀般过去时（be⽤were），主句⽤过去将来时例如：If I were you, I would finish homework first.与过去事实相反从句⽤过去完成时，主句⽤过去将来完成时例如：If I had gone there, I would have bought two tickets.与将来事实相反从句⽤⼀般过去时或过去将来时，主句⽤过去将来时例如：If he had/would have time, he would come to your birthday party tomorrow.2.以even if/though让步从句为虚拟语⽓标志主从句时态同if条件从句相同例如：He might give you more help, even though he were/was very busy.3.以as if/though引导的表语从句或状语从句为虚拟语⽓标志主从句时态同if条件从句相同例如：It seems as if he had known the news.4.以wish后的宾语从句为虚拟语⽓标志与现在事实相反从句时态⽤⼀般过去时（be⽤were）例如：I do wish I knew more about the subject.与过去事实相反从句⽤过去完成时例如：I wish I had seen you yesterday.与将来事实相反从句⽤过去将来时例如：I wish you wouldn't smoke any more.3. 英语中如何区分虚拟语态或假设性的句⼦语⽓是以动词形式表现出来的语法特征，它表⽰说话⼈对事物所持的态度。
虚拟语气if假设句
虚拟语⽓if假设句⼀．分别对过去、现在和未来的假设1、过去发⽣事情进⾏假设这时从句动词⽤had done，主句⽤would/should/could/might+have doneIf you had worked harder, you would have passed your exam.If you had asked me, I would have told you.I would have been in bad trouble if Jane hadn’t helped me.If it hadn’t been for your help, we could have been in lots of trouble.(要不是你的帮助，我们要陷⼊很⼤的⿇烦)2、对现在情形进⾏假设这时从句⽤did和were（be 动词都改成were），主句为would should/could/might+doIf I knew her name, I would tell you.I would perfectly happy, if I had a car.If I were rich，I would spend all my time traveling.If my nose were a little shorter I’d be quite pretty.If it weren’t for the children, we could go skiing.要不是孩⼦们的原因，我们就会去滑雪3、对将来情形假设这时从句有以下三种动词形式 1.were/did 2.were to 3.should 主句为would/should/could/might+do看看下⾯的例⼦What would I do if I were to lose/should lose/lost my job？If you were to move your chair a bit, we could all sit down.if it should rain/were to rain/rained tomorrow, I would not go out.If they should play/were to play / played better next time , they would not fail again上述主句中would最为常⽤，might=would perhaps/would possibly表可能如If you asked me nicely, I might buy you a drink.could=would be able to表能⼒如If I had another $500, I could buy a car.⼆、If it weren’t for…和It hadn’t been for…If it weren’t for…和If it hadn’t been for…，其意为“若不是(有)” “要不是”。
虚拟语气的用法
虚拟语气的用法虚拟语气是英语中一个非常重要的语法现象。
它表示的是假设、愿望、建议、怀疑等语气，与真实情况不同。
在许多场合下，正确地使用虚拟语气可以让我们的表达更加准确、清晰。
本文将系统地介绍虚拟语气的用法及其在各种语境下的运用。
一、虚拟语气的形式虚拟语气的形式有两种：一种是“were to do”(在本文中称作“虚拟语气一型”)，另一种是“should/would/could/might do”等情态动词(在本文中称作“虚拟语气二型”)，它们用于表示假设或愿望等语气情态。
下面我们将详细解释这两种虚拟语气的用法。
二、虚拟语气一型虚拟语气一型的语态如下:1) If I were you, I would…2) I wish I were…3) Suppose he were to…在这些语篇中，“were” 是形式上的一般过去时，但通常表示的是现在或未来的假设情形。
例如，是说：“If I were you,I would go to bed earlier”，而不是像一般过去时一样是“i f I was you, I would go to bed earlier”。
”“were” 代表了一种虚假的情况，所以又称“虚拟语气”。
虚拟语气一型与“if”从句、wish从句、suppose从句等连用常用于表示虚假情况或愿望。
例如：-If I were you, I would goto bed earlier. (如果我是你，我会早睡)-I wish I were rich. (我希望我有钱)-Suppose he were to come today, what would you sayto him? (假设他在今天来，你会对他说什么?)三、虚拟语气二型虚拟语气二型是我们日常生活中用得更多的虚拟语气形式。
它主要由以下情态动词构成：should/would/could/might+动词原形。
这种虚拟语气用于表示一种未来、现在或过去的假设或愿望，也用于表示建议、要求、命令、怀疑等情况。
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引导的虚拟语气时态规则
if引导的虚拟语气时态规则在英语语法中，虚拟语气是一种用来表达假设、愿望、建议或对未来情况的猜测的语法结构。
其中，以if引导的虚拟语气时态规则是其中的一种形式。
本文将详细介绍这一规则的用法和注意事项。
一、虚拟语气的基本概念虚拟语气是一种非真实的语气，用来表达与事实相反或与现实情况不符的假设、愿望或建议。
它通常用于条件句中，以if引导。
虚拟语气有三种时态形式：过去时、过去完成时和过去将来时。
二、以if引导的虚拟语气时态规则1. 过去时虚拟语气当我们想表达与现在事实相反的假设时，可以使用过去时虚拟语气。
其结构为：if + 主语+ 动词的过去式，主语+ would/could/might + 动词原形。
例如：- If I were rich, I would travel around the world.- If she had studied harder, she might have passed the exam.2. 过去完成时虚拟语气当我们想表达与过去事实相反的假设时，可以使用过去完成时虚拟语气。
其结构为：if + 主语+ had + 过去分词，主语+would/could/might + have + 过去分词。
例如：- If I had known the truth, I would have told you.- If they had arrived earlier, they might have caught the train.3. 过去将来时虚拟语气当我们想表达与将来事实相反的假设时，可以使用过去将来时虚拟语气。
其结构为：if + 主语 + should/were to + 动词原形，主语+ would/could/might + 动词原形。
例如：- If it should rain tomorrow, we would stay at home.- If he were to win the lottery, he could buy a new car.三、注意事项1. 在虚拟语气中，动词的形式会发生变化。
if可以引导真实条件句和虚拟条件句.
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 wouldbuy 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 articleearlier, I would not havemade this kind ofmistake.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 raintomorrow, the matchwould be put off. 如果明天下雨，比赛就会被推迟。
三、根据句意及括号中的提示完成句子。
1. —I often get nervous when I have an English class. What should I do?—If I were you, I . (ask the English teacher for help2. —What would the earth be like if there ?(is no air or water on it—It could be like the moon without any living things.3. If it ,the crops would be saved. (is to rain tomorrow4. If we had found him earlier, we .(solve the problem more easily5. If I hadn’t been so busy, I .(take part in the party四、单选。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
一．分别对过去、现在和未来的假设1、过去发生事情进行假设这时从句动词用had done，主句用would/should/could/might+have doneIf you had worked harder, you would have passed your exam.If you had asked me, I would have told you.I would have been in bad trouble if Jane hadn’t helped me.If it hadn’t been for your help, we could have been in lots of trouble.(要不是你的帮助，我们要陷入很大的麻烦)2、对现在情形进行假设这时从句用did和were（be 动词都改成were），主句为would should/could/might+doIf I knew her name, I would tell you.I would perfectly happy, if I had a car.If I were rich，I would spend all my time traveling.If my nose were a little shorter I’d be quite pretty.If it weren’t for the children, we could go skiing.要不是孩子们的原因，我们就会去滑雪3、对将来情形假设这时从句有以下三种动词形式 1.were/did 2.were to 3.should 主句为would/should/could/might+do看看下面的例子What would I do if I were to lose/should lose/lost my job？If you were to move your chair a bit, we could all sit down.if it should rain/were to rain/rained tomorrow, I would not go out.If they should play/were to play / played better next time , they would not fail again上述主句中would最为常用，might=would perhaps/would possibly表可能如If you asked me nicely, I might buy you a drink.could=would be able to表能力如If I had another $500, I could buy a car.二、If it weren’t for…和It hadn’t been for…If it weren’t for…和If it hadn’t been for…，其意为“若不是(有)” “要不是”。
如：If it weren’t for water, no plant could grow. 要是没有水植物就无法生长。
If it hadn’t been for your assistance, we wouldn’t have succeeded.=But for your assistance, we wouldn’t have succeeded.=Without your assistance, we wouldn’t have succeeded.三、含蓄条件句有些句子中虽然没有出现if，但因为but for （要不是），otherwise（否则）等词也暗含着假设，所以要用if假设句的主句动词形式。
如：He would have given you more help,but he was too busy他本来会给你更多的帮助，但是他太忙了。
也就是说，如果那时他不忙，他可以给你更多的帮助。
句中but he was too busy实际上暗示了一个虚拟条件——如果那时他不忙He would lose weight, but he eats too much他本来可以减肥的，但是他吃的太多了。
也就是说，如果他吃得不多的话，他是可以减肥的。
句中的but he eats too much实际上暗示了一个虚拟条件——如果他吃得不多。
Without cars human life would be quite different today. (If there weren’t cars, human life would be quite different today)I am glad you told me about the show being canceled. Otherwise I would havetraveled all the way to London for nothing.(Otherwise=If you hadn’t told me about the show being canceled)He telephoned to inform me of your birthday, or I would have known nothing about it.I might have given you more help, but I was too busy.But for Tom, we could have won the game. (But for Tom=If it hadn’t been for Tom)He telephoned to inform me of your birthday, or I would have known nothing about it.I might have given you more help, but I was too busy.What would you do with a million dollars? ( = if you had a million dollars)We couldn't have finished the work ahead of time without your help. ( = if we hadn't got your help)But for the rain ( = If it hadn't been for the rain ), we would have finished the work.▲四、混合语气前面我们讨论的都是主句和从句在同一时间发生的。
有时主句与从句的动作发生在不同的时间，主句和从句的动词形式因时间不同而不同，此时应根据具体的语境情况，结合上面提到的三种基本类型对时态作相应的调整：我们把它称为混合语气，比如If you had asked him yesterday, you would know what to do now.（从句是过去的假设，主句是现在的结果）If it had rained last night(过去)，it would be very cold today (现在)If I knew you were coming(现在), I’d have baked a cake（过去）.You would be much better now if you had taken my advice. 假若你当时听我的话，你现在就会好多了。
If you had studied hard before, you would be a college student now, and you would graduate from a college i n four years’ time.▲五、假设句的省略与倒装如果if从句中有were，should，had，可以把if省掉，把上述词提前即可：Were they here now, they could help us. = If they were here now, they could help us.他们现在在的话，就会帮助我们了。
Had you come earlier, you would have met him. = If you had come earlier，you would have met him.你来得早一点，就碰到他了。
Should it rain, the crops would be saved. = If it should rain, the crops would be saved.假如下雨，庄稼就有救了。
Had we not missed the plane, we would have been killed in the crash. = if we hadnt missed the plane, we would have been killed in the crash.(不能写成Hadn’t we missed.即had, were, should 提前不能连带not一起写成缩略形式) Were it not for water, no plant could grow.五、假设句的练习2._____ fired, your health care and other benefits will not be immediately cut off. （06湖北卷）A. Would you beB. Should you beC. Could you beD. Might you be答案为B。
本题句意为：如果你被炒了，你的医疗保险和其他利益并不会立即取消。
与将来事实相反。
3.—Is he feeling any better?—No. If he had followed the doctor’s advice, he _____ quite all right now.A. will have beenB. would have beenC. would beD. will be答案为C。
本题为混合时间的虚拟条件句,从句指过去情况，主句为现在情况。
句意：如果他那时接受了医生的建议，现在他就好了。
另外，if引导的虚拟条件句的从句中若含有有were,should或had等，可将if 省略，把were, should或had移至主语前。