If引导的条件状语从句
If引导的条件状语从句（用法）
状语从句：用一个句子（从句）来作另一个句子（主句）的状语，用作状语的句子就叫作
状语从句。作什么样的状语就叫什么类型的状语从句。例如：条件状语从句就是用一个句子
来作条件状语。状语从句的分类：（1）时间状语从句凡是从句都必须有引导词，引导
时间状语从句的词有when，before，after，until，as soon as，while 等。（2）条件状语从句主要看一下由if引导的条件状语从句。if 意为“如果”，引导条件状语从句时，
表示假如有从句的动作发生就（不）会有主句的动作发生。例如：If it doesn't rain to morrow，we will go there by bike.如果明天不下雨，我们就骑自行车去那里。If I g et there early，I can see the doctor quickly.如果我早早地到那里，我就可以快点看病。3）地点状语从句用法要点常用where（哪里）和wherever（无论哪里）eg. Where t here is a will，there is a way. 有志者，事竟成。We will go wherever the mothe rland need us most. 我们要到祖国最需要的地方去。（4）原因状语从句用法要点常用的引导连词有because，as和since，三者的区别是：在回答问题的时候，使用becaus e；对于显而易见的原因，常用as或since；as和since的从句常放在主句之前，而beca use的从句常放在主句之后。eg. Why did you go？I went because Tom told me to go. 你为何去？那是因为汤姆叫我去。He was angry not because we were late but because we made a noise. 他很生气不是因为我们来迟了，而是因为我们弄出了声音。As it was raining hard，we had to be indoors. 由于雨太大，我们只好呆在家里。Since you feel ill，you'd better not go to work. 既然你感觉不舒服，你最好不要去上班了。（5）目的状语从句用法要点常用的引导连词有so that，that和in order that译为：以便，为了，目的是。eg. Please speak more slowly so that we can make full notes. 请讲慢一点，以便我们能作详细笔记。I shall write down your ad
dress that I may not forget. 我要把你的地址记下来，以免忘记。I sent the letter by air mail in order that it might reach him in time. 这封信我以航空信发出，以便他能及时收到。注：目的状语从句可以用动词不定式来替换做目的状语。eg. We work harder than usual finish it in a week. 我们比平常加倍努力工作以在一周内完成工
作。三、主句与从句时态一致的问题。在时间状语从句和条件状语从句中，主句和从句之间的时态一致问题一般分下列两种情况： 1. 若主句是祈使句，或主句中有情态动词，或主
句中谓语动词是一般将来时，那么从句用一般现在时表示一般将来时。例如：Be careful when you cross the road. 过马路时要小心。Put up your hand if you have any questions to ask. 如果你们有问题要问的话，请举手。The traffic must stop when the lights are red. 红灯亮时，车辆必须停下。 2. 若主从句谓语动词都是陈述过去，那
么主从句都可以用一般过去时。例如：She could sing when she was four years ol d. 她四岁的时候就会唱歌。
虚拟语气和if引导的条件状语从句有区别吗？
条件状语从句连接词主要有if, unless, as/so long as, on condition that 等。if 引导的条件句有真实条件句和非真实条件句两种。非真实条件句已在虚拟语气中阐述。
unless = if not. 例如：Let's go out for a walk unless you are too tired.
如果不太累，我们去散散步。If you are not too tied, let's go out for a walk. Y ou will be late ___ you leave immediately. A. unless B. until C. if D.
or 答案A。句意：除非你立即走，否则你就回迟到的。可转化为If you dong leave immediately, you will be late。B、D句意不对，or表转折，句子如为You leave immediately or you will be late. 虚拟语气1）虚拟语气用来表示说话人的主观愿望或假想，所说的是一个条件，不一定是事实，或与事实相反。虚拟语气在条件句中应用
比较多。2）条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条
件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。真实条件句用于陈述
语气，假设的情况有可能发生。一般现在时shall/will + 动词原形祈使句情态动词一般现在时例如：If he comes, he will bring his violin. 如果他来，会带小提琴来的。The volleyball match will be put off if it ___. A. will rain B. rains C. rained D. 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，主句谓语动词不用shall （will）+动词原形，而直接用一般现在时的动词形式。非真实条件句1）虚拟语气可以表示过去，现
在和将来的情况，时态的基本特点是时态往后推移。 a. 与现在事实相反的假设一般过去时（be用were）should（would）等+动词原形例如：If they were here, they would help you. 如果他们在这儿，会帮助你的。含义：They are not here, they can’t help you. b. 与过去事实相反的假设过去完成时should（would）等+ ha ve+ 过去分词例如：If he had come yesterday, I should / would have told hi m about it.如果他昨天来的话，我会把这件事告诉他的。含义：He did not come yesterday, so I did not tell him about it. c. 表示对将来不大可能发生的事情的假
想一般过去时should/would等+ 动词原形were+ 不定式should+ 动词原形例如：If you succeeded, everything would be all right. 如果你将来成功了，一切都会好的。If you should succeed, everything would be all right. If you were t o succeed, everything would be all right. 含义：You are not likely to succee d, everything will be what it is now.
初中英语语法——If引导的条件状语从句(讲解及练习)
条件句从句主句 真实一般现在时一般将来时 情态动词+动原祈使句 非真实 一般过去时 be动词用（were） would/could+动原初中英语――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 1.if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？ 2.unless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。 3.as /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条件状语从句的种类 Ⅳ条件状语从句的时态原则 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。 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. (2)“祈使句 + and (or)+ 陈述句”
if引导的条件状语从句讲解和练习(答案)
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。
初中英语——If引导的条件状语从句
初中英语――if引导的条件状语从句 在主从复合句中修饰主句中的动词、形容词、副词等的从句叫做状语从句，状语从句一般可分为时间状语从句、地点状语从句、原因状语从句、目的状语从句、结果状语从句、条件状语从句、让步状语从句、比较状语从句和方式状语从句九种。 在句子中做条件状语的从句称为条件状语从句。可置于句首、句尾，有时还可置于主语和谓语之间。引导条件状语从句的连接词有：if ,unless,as/so long as等 1.if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？ 2.unless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。 3.as /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。 4.once引导的条件状语从句 once引导的条件状语从句，意为“一旦...，就”，从句可置于主句前或后 Once you begin,never stop. 一旦开始，就绝不要停止 Maths is easy to learn once you understand the rules. 一旦你理解了规则，数学就不难学了。 提示：在条件状语从句中，用一般现在时代替一般将来时，用一般过去时代替过去将来时。 If the weather is bad next week, we'll put off the climbing. 如果下周天气不好，我们将推迟爬山。 Father told me if i worked hard he would buy me a gift. 爸爸告诉我，如果我努力学习，他会给我买一份礼物。
if引导的条件状语从句
语法10单元语法再现梁老师组稿2017-12-31 一、观察下面的句子 If you go to the party, you will have a great time. If you do , you will be late. If you do,you will be sorry. If they have it today, half the class won’t come. If we ask people to bring food, they will just bring potato chips and chocolate. 以上几个句子中“if”有相同的含义“如果”，引导条件状语从句逗号后面的句子是主句。整个连起来的大句子叫主从复合句。 注意主句和从句的时态有什么特点。 总结：If引导的条件状语从句用一般现在时，主句用一般将来时。 简称“主将从现” 练习：（1）If you ______(come)here, you ___________(be) happy. (2) If it _________(rain) tomorrow, we__________(not, go) to the park. (3) If he _________(come) here, I ___________(call) you. (4) If it ___________(not rain), we _________(have) a picnic(野餐). (5) If we do that, more people _________(want) to play the games. 页脚内容1
If引导条件状语从句的详细用法解答
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。
as引导的时间状语从句
as引导的时间状语从句 as是高中英语中非常重要的一个词汇，它的用法非常的复杂，且在每年的高中英语考试中占有非常重要的位置。其中as引导的时间状语从句尤为复杂，本文以as在引导时间状语从句时的三种不同意义为线索，细致讲述as引导时间状语从句这一语法知识点。 as引导时间状语从句表示"当....时候" as在表示"当....时候"的意义时，与"while"引导时间状语从句有一个共同点，就是此时从句的谓语动词一定要用表示延续性的动词。 例句1：She stayed up late writing her paper while our kids and I were sleeping. 当我和孩子们在睡觉的时候，她在熬夜写论文。 注释：这个句中while引导的时间状语从句的谓语动词是表示延续性的"were sleeping"。例句2：They all finished their homework, as I was playing with my dog. 当我在和我的小狗玩耍的时候，他们都完成了家庭作业。 注释：从句中的谓语动词"was playing"是表示延续性的动词。 as引导时间状语从句表示"一边...一边..." 当as表示"一边...一边..."引导时间状语从句时，主句和从句的动作同时发生，此时从句的谓语动词没有要求。 例句1：As she explained her misfortunes, she wiped tears off her cheeks. 她一边讲述着自己的不幸遭遇，一边擦去脸上的泪水。 例句2：She cried as she walked alone on the dark road. 她一边独自走在黑暗的小路上，一边哭泣。
(完整word版)初中英语If引导的条件状语从句
初中英语――if引导的条件状语从句 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.引导条件状语从句的连接词主要有：if(如果）、unless（除非）或as long as （只要）等。unless在意思上等于if...not。 一、条件状语从句用法 1、引导条件状语从句最常用的连词是if,由if引导的条件状语从句表示在某种条件下某事很可能发生。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。 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。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。 2、unless = if...not.除非,若不,除非在……的时候 例如：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,比赛将照常进行。 二、时态问题 在条件状语从句中，要注意“主将从现”的规定，即主句用一般将来时，从句用一般现在时表示将来时。例句： I will come to see you if I have time. 我有时间，我就来看你。 三如果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. 误区提醒 if 既可以引导条件状语从句，表示“如果”，也可以引导宾语从句，表达“是否”。辨别它在这两种从句中的时态是我们经常容易出错的地方。另外，if 和unless的用法也需注意。 典型例题：----I wonder if your wife to the party. ----If your wife _________, so will mine。. A. will go，go B. will go, goes C.goes, will go D. will go, will go 解析：第一句中if表示“是否”，引导宾语从句，用将来时will go；第二句“如果你的妻子去，我的妻子也去”，if引导条件状语从句，用一般现在时表示将来时。your wife，单三人称主语，所以用goes 。
引导的时间状语从句
1.由when, while, as引导的时间状语从句。 When you think you know nothing, then you begin to know something.当你以为自己一无所知的时候，你就是在开始知道一些事物了。When truth is buried under the ground it grows, it chokes, it gathers such an explosive force that on the day it bu rsts out , it blows up everything with it.当真理被埋在地下的时候，它在生长，它感到压抑，它蓄存着这么一种爆炸性力量，一旦冒出，它就会炸破一切！ Strike while the iron is hot. 趁热打铁。 Will you watch my clothes while I have a swim? 我游泳的时候，请你照看一下我的衣服。 You can feel the air moving as your hand pushes through it . 当你的手在空气中挥动的时候，你就能感觉到空气在流动。 Our headmaster laughed as she spoke.我们的校长边谈边笑。 when, while和as的区别 1. when引导的从句的谓语动词可以是延续性的动词，又可以是瞬时动词。并且when有时表示“就在那时”。 例如： When she came in, I stopped eating.她进来时，我在吃饭。(瞬时动词) When I lived in the countryside, I used to carry some wate r for him.当的住在农村时，我常常为他担水。（延续性的动词） We were about to leave when he came in.我们就要离开，就在那时他进来了。 2. While引导的从句的谓语动作必须是延续性的，并强调主句和从句的动作同时发生（或者相对应）。并且while有时还可以表示对比。例如： While my wife was reading the newspaper, I was watching TV. (was reading是延续性的动词，was reading和was watching同时发生) I like playing football while you like playing basketball.我喜欢踢足球，而你喜欢打篮球。（对比） 3. As表示“一边……一边”，as引导的动作是延续性的动作，一般用于主句和从句动作同时发生；as也可以强调“一先一后。例如： We always sing as we walk.我们总是边走边唱。（as表示“一边……一边”） As we was going out, it began to snow.当我们出门时，开始下雪了。（as强调句中两个动作紧接着先后发生，而不强调开始下雪的特定时间） as when while的辨析 as when while都表示主、从句动作同时发生，三者差异如下：
when,while,as引导时间状语从句的区别
when，while，as引导时间状语从句的区别 when，while，as显然都可以引导时间状语从句，但用法区别非常大。 一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。 ①Why do you want a new job when youve got such a good one already？（get 为短暂性动词）你已经找到如此好的工作，为何还想再找新的？ ②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。 ③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。 ④The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。 二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while 和as从句的谓语动作必须是和主句谓语动作同时发生。 1．从句动作在主句动作前发生，只用when。 ①When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。 ②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，客人们已经离开了。 2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。 ①When ／While ／As we were dancing，a stranger came in．（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。 ②When ／While ／As she was making a phonecall，I was writing a letter．（make为延续性动词）当她在打电话时，我正在写信。 3．当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用as。这时，as常表示“随着……”；“一边……，一边……”之意。 ①As the time went on，the weather got worse．（as表示“随着……”之意） ②The atmosphere gets thinner and thinner as the height increases．随着高度的增加，大气越来越稀薄。 ③As years go by，China is getting stronger and richer．随着时间一年一年过去，中国变得越来越富强了。 ④The little girls sang as they went．小姑娘们一边走，一边唱。 ⑤The sad mother sat on the roadside，shouting as she was crying．伤心的妈妈坐在路边，边哭边叫。 4．在将来时从句中，常用when，且从句须用一般时代替将来时。 ①You shall borrow the book when I have finished reading it．在我读完这本书后，你可以借阅。 ②When the manager comes here for a visit next week，Ill talk with him about this．下周，经理来这参观时，我会和他谈谈此事。 三、when用于表示“一……就……”的句型中（指过去的事情）。 sb．had hardly（＝scarcely）done sth．when．．．＝Hardly ／Scarcely had sb．done sth．when．．．
if条件状语从句专练
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
If 引导的条件状语从句
If 引导的条件状语从句 If 引导的条件状语从句遵循主过从过、主将从现的原则。 主将从现（主情从现、主祈从现） If it rains tomorrow,I won’t climb the hills. If it doesn’t rain tomorrow,I will go to the countryside with my friends. If 引导的条件状语从句 If 引导的条件状语从句遵循主过从过、主将从现的原则。 主将从现（主情从现、主祈从现） If you will help me,I'll finish it on time. We may go out if it's fine tomorrow. If you finish your homework,you can watch TV. Please call me if you go shopping next Sunday. If I go there，I'll take her some flowers. We'll stay at home if it rains tomorrow. Please call me if he’s at home. If you work harder,you’ll pass the exam. She will visit her grandpa if she has time tomorrow. We’ll take a taxi to the city if the train doesn’t arrive on time. The teacher will be angry if he is late. If引导的条件状语从句与unless引导的条件状语从句的转换 If+否定形式=unless+肯定形式
if引导的条件状语从句-与专题练习
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。如： If you ask me ,I will answer you． If it rains tomorrow, I will stay at home. I will stay at home if it rains tomorrow. 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 in university，I would …． If I had enough money ,I would buy a car. 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． 2.if从句用一般现在时，主句用may/might/can/must If the fog gets thicker the plane may/might be diverted. 3.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) 4. 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. 5.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.
as引导的五种状语从句
as作从属连词用时,可以引导五种状语从句。现归纳如下： 1. as表示“当……的时候”,引导时间状语从句,多强调主句和从句中的动作或状态同时发生,从句可放在主句前,也可放在主句后。例如： As I waited at the stop, I heard a big noise. 当我在车站等车的时候,我听到一个很大的声响。 She rose up as he entered. 当他进来时,她站了起来。 2. as表示“因为”、“由于”,引导原因状语从句,其语气不如because强,通常为附加说明的理由,且是已知晓的原因,主句与从句没有逻辑上的因果关系。例如： As she was not well, I went there alone. 因为她身体不好,所以我独自到那里去了。 As he is a tailor, he knows what to do with this material. 由于他是个裁缝,他知道怎样利用这块布料。 3. as表示“虽然……但是……”,引导让步状语从句,从句通常用倒装语序,把从句的表语、状语或动词原形放在as前面,可以用though替代。例如： Child as he is, he knows a lot. 虽然他是个孩子,但他知道的东西很多。 Hard as it was raining, they went on working in the field. 虽然天下大雨,但他们继续在田地里干活。 4. as表示“按照”、“依照”、“像”,引导方式状语从句,从句置于主句之后。例如： You should do as the teacher tells you.你应当依照老师所说的去做。 The absence of air also explains why the stars do not seem to twinkle in space as they do from the earth. 空气的不存在,也说明了为什么在空中星星看来并不闪烁,而不像从地球上看的那样。 5. as表示“像……一样”,引导比较状语从句,对主句和从句的动作或状态加以比较,说明它们之间有相似之处,在从句中常省略与主句相同的部分。例如： He doesn't work as hard as I (do). 他不像我工作那样努力。 I hope the necklace was as good as the one you lent me.我希望我挂项链同你借给我的一样好。
总结好的：if引导的条件状语从句
if引导的条件状语从句 if 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。如： Please call me if he comes next Sunday. Can you call the policeman if you are in the trouble. 注意宾语从句中的if与条件状语从句if的区别。宾语从句中的if“是否”相当于whether，引导宾语从句，时态需根据语境确定。如果主句用一般现在时，从句可以根据具体情况选用时态，如果主句用一般过去时，从句必须用过去式的某种形式。 I don't know if it will rain tomorrow. 我不知道明天是否会下雨。 Our teacher said there was going to be a football match the next month.我们说下月将有场足球比赛。 【边学边做】用括号内所给词的正确形式填空。 1. What will you buy if you ________（have）a lot of money? 2. If it ________（not snow）tomorrow, we will feel unhappy. 3. You mustn’t go to school if you ________（be）still in bed. 4. If he _______（be）at home at that time, he would know it. 5. Please show me the way if you ________（know）it. 6. You will hurt your teeth if you ________（eat）too much candy. 7. If you gave me a toy car, I _________（be）very happy. 8. I would get the prize if I _________（work）hard. 9．If she ______ (finish ) work early ,she ______(go) home. 10．If the weather______（be）fine，we_______(go)for a walk .
if条件状语从句练习及答案
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 you _____ to the party, you’ll have a great time. a. will go b. went c. go d. going 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 ’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 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?
When,While,As引导时间状语从句的区别之欧阳家百创编
When，While，As引导时间状语从句的区别 欧阳家百（2021.03.07） when，while，as显然都可以引导时间状语从句，但用法区别非常大。 一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。 ① Why do you want a new job when you’ve got such a good one already？（get为短暂性动词）你已经找到如此好的工作，为何还想再找新的？ ②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。 ③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。 ④ The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。 二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。 1．从句动作在主句动作前发生，只用 when。
①When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。 ②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，客人们已经离开了。 2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。 ①When ／While ／As we were dancing，a stranger came in．（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。 ②When ／While ／As she was making a phone call，I was writing a letter．（make为延续性动词）当她在打电话时，我正在写信。 3．当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时，as常表示“随着……”；“一边……，一边……”之意。 ① As the time went on，the weather got worse．（as表示“随着……”之意） ② The atmosphere gets thinner and thinner as the height increases．随着高度的增加，大气越来越稀薄。 ③As years go by，China is getting stronger and richer．随着时间一年一年过去，中国变得越来越富强了。 ④The little girls sang as they went．小姑娘们一边走，一边唱。 ⑤The sad mother sat on the roadside，shouting as she was crying．伤心的妈妈坐在路边，边哭边叫。