20XX状语从句用法讲解和练习
(完整版)状语从句详解+例句
(完整版)状语从句详解+例句状语从句是指在复合句中充当状语的从句。
状语从句可以用来表示时间、原因、条件、目的、程度、方式等各种状况。
下面将详细介绍状语从句的各种类型及其例句。
1. 时间状语从句时间状语从句用来表示主句所描述的行为或状态发生的时间。
常用的连接词有when（当...时候）、while（当...期间）、as（当...时）、before（在...之前）、after（在...之后）、since（自从）等。
例句：- I will call you when I arrive in Beijing.（当我到达北京时，我会给你打电话。
）- He was reading a book while she was cooking.（她在做饭的时候，他在看书。
）2. 原因状语从句原因状语从句用来表示主句所描述的行为或状态的原因。
常用的连接词有because（因为）、since（因为）、as（由于）、for （因为）等。
例句：- I can't go to the party because I have to work.（我不能去参加派对，因为我得工作。
）- Since it is raining, we should stay at home.（由于下雨了，我们应该待在家里。
）3. 条件状语从句条件状语从句用来表示主句所描述的行为或状态的前提条件。
常用的连接词有if（如果）、unless（除非）、whether（无论）、provided（倘若）等。
例句：- If it rains tomorrow, we will stay indoors.（如果明天下雨，我们会呆在室内。
）- We can go shopping unless it is too late.（除非太晚，否则我们可以去购物。
）4. 目的状语从句目的状语从句用来表示主句所描述的行为或状态的目的。
常用的连接词有so that（以便）、in order that（为了）、lest（免得）等。
状语从句讲解及习题附答案
状语从句（一）状语从句概述（二）状语从句详解1. 时间状语从句2.地点状语从句3.条件状语从句4.原因状语从句5.目的状语从句6.结果状语从句7.让步状语从句8. 比较状语从句9.方式状语从句练习一一. 单项填空1. _______ he’s old, he can still carry this heavy bag.A. ThoughB. SinceC. ForD. So2. ---Do you know if he _______ to play basketball with us?---I think he will come if he ______ free tomorrow.A. comes; isB. comes; will beC. will come; isD. will come; will be3. In the zoo if a child _____ into the water and can’t swim, the dolphins may come up ______ him.A. will fall; to helpB. falls; to helpC. will fall; helpD. falls; helping4. I don’t remember ________ he worked in that city when he was young.A. whatB. whichC. whereD. who5. We will stay at home if my aunt ________ to visit us tomorrow.A. comesB. comeC. will comeD. is coming6. The police asked the children _______ cross the street ________ the traffic lights turned green.A. not; beforeB. don’t; whenC. not to; untilD. not; after7. I was late for class yesterday _______ there was something wrong with my bike.A. whenB. thatC. untilD. because8. I’ll go swimming with you if I ________ free tomorrow.A. will beB. shall beC. amD. was9. In the exam, the ________ you are, ______ the _______ mistakes you will make.A. careful; littleB. more careful; fewestC. more careful; fewerD. more careful; less10. You should finish your lessons _______ you go out to play.A. beforeB. afterC. whenD. while11. I hurried _____ I wouldn’t be late for class.A. sinceB. so thatC. as ifD. unless12. When you read the book, you’d better make a mark _______ you have any questions.A. whichB. thatC. whereD. though13. The teacher raised his voice _______ all the students could hear him.A. forB. so thatC. becauseD. in order14. He took off his coat _______ he felt hot.A. becauseB. asC. ifD. since15. It is ______ that we’d like to go out for a walk.A. a lovely dayB. too lovely a dayC. so lovely a dayD. such lovely a day16. Mary had ______ much work to do that she stayed at her office all day.A. suchB. soC. tooD. very17. _______ I felt very tired, I tried to finish the work.A. AlthoughB. BecauseC. AsD. As if18. ______ the day went on, the weather got worse.A. WithB. SinceC. WhileD. As19. ______ well you can drive, you must drive carefully.A. So long asB. In order thatC. No matter howD. The moment20. Write to me as soon as you ________ to Beijing.A. will getB. getC. gettingD. got二. 根据中文意思完成下列英语句子1. 不管他跟我开什么玩笑，我都不生气。
20XX中考英语状语从句专题复习含答案解析
必备英语中考英语状语从句专题复习含答案解析一、初中英语状语从句1．He made a serious mistake, but he took immediate action to change that ______ it got worse. A．until B．when C．because D．before【答案】D【解析】试题分析：句意：他犯一个严重的错误。
但他采取行动来改变它以免变得更糟。
A. Until直到；B. When当……时；C. Because因为；D. Before在……之前。
在变得更糟之前采取行动改变。
故选D。
考点：考查连词辨析。
2．—I’m going to the post office.—________you are there, can you get me some stamps?A．When B．While C．Because D．If【答案】B【解析】试题分析：A. As 一边…一边，作为 B. While当…时候 C. Because 因为 D. lf假如；句意：我将要去邮局。
你去那里的时候，能不能给我带一些邮票呢？故选B考点：连词点评：连词在中考中涉及到的很多，尤其在宾语从句、状语从句、定语从句中连词是必考点。
平时学习过程中，掌握连词的意思，及所表示的关系是至关重要的，这种关系的判断可以通过句子意思的理解来选择恰到的连词。
3．---Could you give me some advice on travelling?---Take a map with you _______ you have a guide or you know the city very well.A．if B．unless C．although D．because【答案】B【解析】句意：--你能给我一些关于旅行的建议吗？--如果没有向导或者对城市不很了解，那么就随身带着一张地图。
高考英语《连词与状语从句》复习题及解析
高考英语《连词与状语从句》复习题及解析高考英语《连词与状语从句》复习题及解析我们都知道，英语语法是英语体系的钢筋铁骨，所有的口语及书面表达都需要依附英语语法而成，其中高考时英语语法更是贯穿了整张卷面。
下面是店铺整理的高考英语《连词与状语从句》复习题及解析，希望对你有所帮助。
高考英语《连词与状语从句》复习题及解析篇11.【20XX届山西忻州一中康杰中学临汾一中长治二中高三第二次联考】You should try to get a good night sleep __________ much work you have to do.A. howeverB. whateverC. no matterD. although【解析】A考查让步状语从句。
句意：无论你有多少工作要做，你应该保证有充足的睡眠。
However /no matter how可以引导让步状语从句，结构是：However/no matter how+adj/adv.+主语+谓语，B项whatever应该接名词，C项少了how，D项although不能接倒装句，选A项。
2.【20XX届北京市第四十四中学高三第一学期期中测试】________ I say Clancy is a smart boy, he still needs to work hard to achieve his goal.A. Th enB. WhenC. WhileD. As【解析】C考查连词的用法。
句意：虽然我说Clancy是一个聪明的孩子，但他仍需努力工作来实现他的目标。
as引导让步状语从句时，需要倒装，所以排除。
故选C项。
3.【20XX届北京市第四十四中学高三第一学期期中测试】_________ , the players began the game.A. Having taken our seatsB. Taking our seatsC. Being taken the seatsD. After we had taken our seats【解析】D考查状语从句的用法。
状语从句的讲解和练习
状语从句的讲解和练习一、经典讲解在复合句中修饰主句中的动词、形容词或副词等的句子叫状语从句。
状语从句根据它表达的意义的不同可分为：时间状语从句、原因状语从句、条件状语从句、比较方式状语从句、目的状语从句、结果状语从句和让步状语从句。
如果状语从句放在主句前，通常在从句后用逗号隔开。
（一）时间状语从句其连接词有：when，while，before，after，since，till（until），as soon as 等。
由这些连词引导的主从复合句中的主句和从句谓语动词发生的时间有三种情况，即同时发生和先后发生。
因此在运用时间状语从句时，特别要注意主句和从句之间的时态呼应。
1. when引导的从句有时主句的动作和从句的动作同时发生，有时主句的动作在前，从句的动作在后。
如果主句用一般将来时，则从句就要用一般现在时。
Tom will go to see her when he has time.It was raining when I left the hospital.The film had already began when I got to the cinema.2. 由while 引导的从句表示正在进行某一动作时另一动作发生了；还可以表示某个动作还在进行的同时，另一个动作也在进行之中。
例如：While he was reading, the telephone rang.While we were boating on the lake, we saw a fish jump out of the water.While my sister was watching TV, I was writing.While Dad was washing his car, Mum was cooking.3. 由before 引导的从句在由before 引导的从句中，一般来说主句的动作发生在从句的动作之前，主从句的动词都用过去时。
状语从句讲解及练习
状语从句讲解及练习状语从句的析与练用来修饰主句中的动词，形容词或副词等而充当状语的从句叫做状语从句。
状语从句常用从属连词来引导，与主句连接起来。
若置于句末，则前面不加逗号。
根据意义和作用，状语从句可分为时间原因条件等几种。
下面我们就来分析一下这几种状语从句。
1时间状语从句时间状语从句常用从属连词when, after, until, as soon as, 等来引导。
当主句是祈使句或谓语动词是一般将来时态或情态动词时，其时间状语从句中的谓语动词常用一般现在时态表示将来发生的动作或存在的状态。
这就是我们常说的“主将从现”。
如：Please call me when you get there. 当你到那时，请给我打个电话。
I will write to you as soon as I arrive in Beijing. 我一到北京就给你写信。
<温馨提示>since 引导时间状语从句表示“自从…以来”，从句中的动词一般表示动作的起点，用过去时；而主句的动作延续的情况则用一般现在时或现在完成时。
常用的句型为：It has been/ is + 一段时间+ since + 过去时。
如：I has been/ is three years since we met last time. 自从我们上次见面，已经三年了。
2条件状语从句引导条件状语从句的连词或词组有：if （如果), unless（除非）, as long as（只要）等。
如果主句是将来时，条件状语从句也用一般现在时来表示。
如：I will stay at home if it rains tomorrow. 如果明天下雨，我就待在家。
You can’t learn English well unless you work hard.除非你努力学习，否则是学不好英语的。
<温馨提示>由if 引导的条件状语从句，若从句表达的是与现在事实相反的事实，则常用虚拟语气，即用过去时态表示（如果涉及到be 动词，一律都用were）。
状语从句总结及例题_状语从句 英语语法.doc
状语从句总结及例题_状语从句由从句担任的状语，在句子中可修饰谓语（或其它动词）、形容词、副词或是整个句子，它可以用来表示时间、地点、原因、目的、结果、条件、方式、比较、让步等。
状语从句是一较大的语法项目，也是近几年高考题中常见的一个重要试点。
高考中已考查了时间、让步、地点、条件、目的等状语从句，这些从句仍是今后高考热点，应作充分准备。
同时对方式状语从句也应引起重视。
（一）时间状语从句表示时间的状语从句可由when, as, while, whenever, after, before, till (until), since, once, as soon as (或the moment ), by the time, no sooner than, hardly (scarcely) when, every time等引导。
e.g. When I came into the office, the teachers were having a meeting.He started as soon as he received the news.Once you see him, you will never forget him.No sooner had I gone to bed than I went to sleep.（二）原因状语从句原因状语从句是表示原因或理由的，引导这类从句的最常用的连词是because, since, as , now that（既然）等，for 表示因果关系时（它引导的不是从句）为并列连词，语气不如because强。
e.g. He is disappoi nted because he didn’t get the position.As it is raining, I will not go out.Now that you mention it, I do remember.（三）地点状语从句引导地点状语从句的连词是where 和wherever等。
状语从句的位置和作用解析与实例练习
状语从句的位置和作用解析与实例练习状语从句是句子中的一个从句，用来修饰主句中的动词、形容词、副词等词语，起到限制、补充或者修饰的作用。
在句子中，状语从句的位置可以灵活变化，但在不同的位置上，状语从句会有不同的作用和语义。
一、状语从句的位置1. 在句首位置状语从句放在句首时，可以起到引导整个句子的作用，强调句子的条件、原因、目的等。
例1：如果你明天有时间，我会带你去游乐园。
例2：虽然天气很热，人们还是热衷于户外运动。
2. 在句中位置状语从句放在句中时，可以起到补充、解释、转折等作用，使句子更加详细或者丰富。
例1：我们昨天去了一个很有趣的地方，那里有很多野生动物。
例2：他们虽然工作很忙，但是还是抽出时间来教我们英语。
3. 在句末位置状语从句放在句末时，可以起到总结、强调、对比等作用，使句子更加完整或者有助于突出主要信息。
例1：我会尽快完成这份报告，不管有多么困难。
例2：他一直努力学习，终于考上了理想的大学。
二、状语从句的作用1. 修饰动词状语从句可以修饰主句中的动词，表达动作的条件、原因、目的等。
例1：如果你喜欢，我们可以一起去看电影。
例2：她来了以后，我们才开始吃饭。
2. 修饰形容词状语从句可以修饰主句中的形容词，用来补充或者解释形容词所表达的程度或者状态。
例1：这个问题太复杂，以至于我们无法解决。
例2：她的演讲非常生动，以至于观众都被吸引住了。
3. 修饰副词状语从句可以修饰主句中的副词，表达副词的限制或者强调。
例1：他跑得太快，以至于我追不上他。
例2：她每天都早早地来到学校，以便能有更多的时间准备。
三、状语从句的实例练习1. 完成下列句子，用适当的状语从句：a. ______________________________，我会给你答复。
b. 我每天早早起床，_________________。
c. ______________________________，他依然坚持下去。
（参考答案）a. 如果你有什么问题，我会给你答复。
状语从句讲解及练习(附答案解析)
状语从句主要用来修饰主句或主句的谓语。
一般可分为九大类,分别表示时间、地点、原因、目的、结果、条件、让步、比较和方式。
尽管种类较多,但由于状语从句与汉语结构和用法相似,所以理解和掌握它并不难。
状语从句的关键是要掌握引导不同状语从句的常用连接词和特殊的连接词即考点。
现分别列举如下:1、时间状语从句常用引导词:when, as, while, as soon as, while, before, after, since , till, until特殊引导词:the minute, the moment, the second, every time, the day,the instant, immediately , directly, no sooner … than, hardly …when, scarcely … whenI didn't realize how special my mother was until I became an adult.While John was watching TV, his wife was cooking.The children ran away from the orchard(果园) the moment they saw the guard.No sooner had I arrived home than it began to rain.Every time I listen to your advice, I get into trouble.2、地点状语从句常用引导词:where特殊引导词:wherever, anywhere, everywhereGenerally, air will be heavily polluted where there are factories.Wherever you go, you should work hard.3、原因状语从句常用引导词:because, since, as, for特殊引导词:seeing that, now that, in that, considering that, given that, considering that, as much as, so much asMy friends dislike me because I'm handsome and successful.Now that everybody has come, let's begin our conference.The higher income tax is harmful in that it may discourage people from trying to earn more.Considering that he is no more than 12 years old, his height of 1.80 m is quite remarkable.4、目的状语从句常用引导词:so that, in order that特殊引导词:lest, in case, for fear that,in the hope that, for the purpose that, to the end thatThe boss asked the secretary to hurry up with the letters so that he could sign them.The teacher raised his voice on purpose that the students in the back could hear more clearly.5、结果状语从句常用引导词:so that, so… that, such … that,特殊引导词:such that, to the degree that, to the extent that, to such a degree that, He got up so early that he caught the first bus.It's such a good chance that we must not miss it.To such an degree was he excited that he couldn't sleep last night.6、条件状语从句常用引导词:if, unless,特殊引导词:as/so long as, only if, providing/provided that, suppose that, in case that, on condition thatWe'll start our project if the president agrees.You will certainly succeed so long as you keep on trying.Provided that there is no opposition, we shall hold the meeting here.7、让步状语从句常用引导词:though, although, even if, even though特殊引导词: as(用在让步状语从句中必须要倒装),while ( 一般用在句首),no matter …, in spite of the fact that, while, whatever, whoever, wherever, whenever, however, whicheverMuch as I respect him, I can't agree to his proposal.尽管我很尊敬他, 我却不同意他的建议。
(完整版)高中英语状语从句讲解及练习
状语从句状语从句在句中作状语，可分为：时间、条件、让步、原因、目的、结果、比较、地点、方式状语从句。
一、时间状语从句弓丨导时间状语从句的连词有：whe n, as, while, un til, not …un til, before, after, sin ce, the minute,the moment, each( every, next, the first) time 等。
时间状语从句中一般用一般现在时或一般过去时。
1. When , while, as都可解释为"当'、'的时候”但侧重点有所不同。
1) WhenEg: When I arrived home , I had a little rest.注意点：when从句的主语与主句主语相同，谓语动词是be动词时，从句主语和be可以省略。
Eg: When (she was) walking along the street, she met her class teacher.2) AsAs 除了表示“当'''的时候”，还可表示为“一面'''一面”，“随着”Eg: He sang as he danced.一面'''一面)You will grow wiser as you grow older.( 随着)3) While 表示“当'''的时候” 强调主句的动作和从句的动作同时发生，从句一般用进行时，从句动词必须是延续性动词。
Eg: While we were working, they were having a rest.While (they were) having a discussion, they got very confused.注意点：while 有对比的含义，解释为“然而” 。
eg: I prefer black tee, while he likes coffee.2. until, not…until表示"直到'、'才”，在肯定句中主句常用延续性动词；在否定句中主句常用短暂性动词。
高中英语状语从句讲解及练习
状语从句状语从句在句中作状语，可分为：时间、条件、让步、原因、目的、结果、比较、地点、方式状语从句。
一、时间状语从句引导时间状语从句的连词有：when, as, while, until, not…until, before, after, since, the minute, the moment, each( every, next, the first) time 等。
时间状语从句中一般用一般现在时或一般过去时。
1．When , while, as都可解释为“当```的时候”但侧重点有所不同。
1)WhenEg: When I arrived home , I had a little rest.注意点：when 从句的主语与主句主语相同，谓语动词是be 动词时，从句主语和be可以省略。
Eg: When (she was) walking along the street, she met her class teacher.2)AsAs 除了表示“当```的时候”，还可表示为“一面```一面”，“随着”Eg: He sang as he danced.(一面```一面)You will grow wiser as you grow older.(随着)3)While表示“当```的时候”强调主句的动作和从句的动作同时发生，从句一般用进行时，从句动词必须是延续性动词。
Eg: While we were working, they were having a rest.While (they were) having a discussion, they got very confused. 注意点：while 有对比的含义，解释为“然而”。
eg: I prefer black tee, while he likes coffee.2．until, not…until表示“直到```才”,在肯定句中主句常用延续性动词；在否定句中主句常用短暂性动词。
状语从句的用法及练习
状语从句的用法及练习状语从句指句子用作状语时，起副词作用的句子。
它可以修饰谓语、非谓语动词、定语、状语或整个句子。
根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。
那么你知道状语从句的用法吗?下面跟着店铺一起来学习一下，希望对大家的学习有所帮助!一、状语从句的用法1、时间状语从句常用引导词:when, as, while, as soon as, while, before, after, since , till, until特殊引导词:the minute, the moment, the second, every time, the day,the instant, immediately , directly, no sooner … than, hardly …when, scarcely … whenI didn't realize how special my mother was until I became an adult.While John was watching TV, his wife was cooking.The children ran away from the orchard(果园) the moment they saw the guard.No sooner had I arrived home than it began to rain.Every time I listen to your advice, I get into trouble.2、地点状语从句常用引导词:where特殊引导词:wherever, anywhere, everywhereGenerally, air will be heavily polluted where there are factories.Wherever you go, you should work hard.3、原因状语从句常用引导词:because, since, as, for特殊引导词:seeing that, now that, in that, considering that,given that, considering that, as much as, so much asMy friends dislike me because I'm handsome and successful.Now that everybody has come, let's begin our conference.The higher income tax is harmful in that it may discourage people from trying to earn more.Considering that he is no more than 12 years old, his height of 1.80 m is quite remarkable.4、目的状语从句常用引导词:so that, in order that特殊引导词:lest, in case, for fear that,in the hope that, for the purpose that, to the end thatThe boss asked the secretary to hurry up with the letters so that he could sign them.The teacher raised his voice on purpose that the students in the back could hear more clearly.5、结果状语从句常用引导词:so that, so… that, such … that,特殊引导词:such that, to the degree that, to the extent that, to such a degree that,He got up so early that he caught the first bus.It's such a good chance that we must not miss it.To such an degree was he excited that he couldn't sleep last night.6、条件状语从句常用引导词:if, unless,特殊引导词:as/so long as, only if, providing/provided that, suppose that, in case that, on condition thatWe'll start our project if the president agrees.You will certainly succeed so long as you keep on trying.Provided that there is no opposition, we shall hold themeeting here.7、让步状语从句常用引导词:though, although, even if, even though特殊引导词: as(用在让步状语从句中必须要倒装),while ( 一般用在句首),no matter …, in spite of the fact that, while, whatever, whoever, wherever, whenever, however, whicheverMuch as I respect him, I can't agree to his proposal.尽管我很尊敬他, 我却不同意他的建议。
(完整word)高中英语状语从句讲解及练习.doc
状从句在复合句中作状，位置灵活。
状从句可分状从句，目的状从句，条件状从句，步状从句，地点状从句，原因状从句，方式状从句，果状从句。
（一）状从句1. when, as, whilea. when 表，从句既可以用延性，又可以用瞬。
Eg: When I get there I will call you.如果 when 引的状的主与主句的主相同，而从句的又是be ，那么从句中的主与be 可省。
Eg： When （ you are） in trouble, you can ask her for help.如果 when 引的状的主与主句的主相同，往往可以用“when+分”的形式代替状从。
Eg： When I came into the room(When coming into the room), I found the light was off.b.while 表，从句需用延性，或者主句的作生在从句的作行程中。
主句的通常是非延性。
Eg: He came in while I was reading a book.I met her while I was in school.c. as 表，与 when 相似，但重主从句作同在点或同段行。
同可表示主句的作随着从句的作的化而化。
Eg: He jumps as he sings.As the wind rose, the noise increased.2.before(在⋯⋯之前 )与 after（在⋯⋯之后）Eg：See me before you leave.I saw them after I arrived.3.till 与 until肯定形式表示的意思是" 做某事直至某"。
否定形式表达的意思是"直至某才做某事" 。
Eg: Wait till/untill I call you.等着直到我叫你。
She didn't arrive till/until 6 o'clock..她直到 6 点才到但是置于句首只可用untill.Until you told me, I had heard nothing of what happened.直到你告我以前，出了什么事我一点也不知道。
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第章状语从句学习指导状语从句在句子中作状语，用来修饰主句或主句的谓语。
一般可分为九大类，分别表示时间、地点、原因、目的、结果、条件、让步、比较和方式。
尽管种类较多，但由于状语从句与汉语结构和用法相似，所以理解和掌握它并不难。
状语从句的关键是要掌握引导不同状语从句的常用连接词。
现分别列举如下：状语从句分九类：在这一章节的学习中，要求同学们掌握各类状语从句基本概念，并能够灵活应用。
第一节时间状语从句时间状语从句用一般现在时表示将来。
连接时间状语从句的连接词有：2. when, while, as均可表示“当.... 的时候”。
when强调“特定时间”，表示主句谓语动词的动作与从句谓语动词的动作是同时发生的，或从句的动作发生在主句的动作之前；while表示的时间是一段，而不是一点，as多用在口语中，强调“同一时间” 或“一前一后”，有时还有“随着”的含义。
When spring came, he felt like a trip 春天来了，他想去旅游。
As spring warms the good earth, all flowers begin to bloom . （as有“随着”的含义）as, whe n, while都表示主、从句的动作或状态同时发生，但三者也有区别。
as和when引导的从句既可表示一点时间，也可表示一段时间，从句中的谓语动词既可以是持续性动词，也可以为短暂性动词，经常可以互换使用；while引导的从句通常表示一段时间，从句中宜用持续性动词作谓语。
当从句中的谓语动词为持续性动词时，这三者可以通用（前面例句中已有体现），再如：1 / 18Mother was worried because little Alice was ill, especially as / when / whilefather was away in Fra nee妈妈担心，因为小艾丽思病了，特别是当父亲远在法国的时候。
如果从句和主句要表示一个人的两个动作交替进行或同时完成时，则多用as,可译为“一边……，一边……”。
例如：He looked beh ind from to time as he we nt.他一边走，一边不时地往后看。
As time goes on, it's getting warmer and warmer.随着时间的推移，天气变得越来越暖了。
I thought of it just as you ope ned your mouth.你一张嘴我就知道你要说什么。
（若表示两个短促动作几乎同时发生时，用as的场合多于whe n.）当主从句之间表示转折或对比关系时，多用while,不用as或when。
如：She thought I was talking about her daughter, while in fact, I was talking aboutmy daughter她以为我在谈论她女儿，而事实上，我在谈论我的女儿。
如果表示从句的动作在主句的动作“之前”或“之后”发生时，多用when（二after）,不用as或while。
此外，when 还含有“at that moment ” 的意思（二and then）,引起的句子不能放在句首，也不能用as, while来替换。
例如：He was about to leave whe n the telepho ne rang 他正要离开，忽然电话铃响了。
We were watchi ng TV whe n sudde nly the lights went out 我们正在看电视，突然灯灭了。
They had just arrived home when it began to rain他们刚到家，天就开始下雨了。
3. till /until，表示“一直到... ”，主从句都用肯定式；表示“直到.... 才”,主句否定，从句肯定。
He worked un til it was dark.他一直工作至U天黑。
2 / 18He did not get up till his mother came in. —直至U母亲进来他才起床。
4. once “一旦”，by the time “到 .. 时”。
Once you see her, you will find what I said is true. 一旦你见至U她就会发现我说的是对的by the time+现在时，主句用将来完成时。
By the time he arrives, we will already have left here.等他至U达时，我们将已离开这儿了。
by the time+一般过去时，主句用过去完成时。
By the time he arrived, we had already left here 他到达的时候我们早已离开这儿了。
5. as soon as the moment表示从句动作一发生，主句动作随即发生，通常译为“一....就”。
As soon as I fin ish the work, I 'll go to see you.我一完成工作就会来看你。
She came to the sce ne the mome nt she heard the n ews她一听至U消息就来到现场。
6. since “ 自从” , before “在 . 前” ,after “在... 后” ,It was not long before 意为“不久”。
since引导从句用非延续性动词或“过去时间点”或“过去时间段+ago”，主句用完成时态。
Since he graduated, he has worked in this city.他毕业后一直在这个城市工作。
I have n't see n him si nce last year/ three years ago.去年以来/3 年来，我没见过他。
选出最佳答案3 / 181) he was liste ning to the music, Joh n fell asleep.A. AfterB. BeforeC. WhileD. As soo n as-2) How did you try to get to school on time you missed the school bus.A. whenB. howC. whyD. that3) He was riding to school he was hit by a car this morning.A while B. whe n C. as D. so4) Lucy knew nothing about it her sister told her.A. becauseB. un tilC. ifD. since5) The policema n asked the child cross the street the traffic lights tur ned gree n.A. not; whe nB. don't; beforeC. not to; un tilD. not to; since6) The book was so interesting that he had read it for three hourshe realized it.A. whe nB. afterC. un tilD. before7) we had see n all the ani mals, we went home.A. ThenB. AfterC. ThoughD. While8) She has made many friends she came to our school.A. beforeB. afterC. si nceD. un til9) —How long has the weather been like this?A. Un til last ni ghtB. Ever since last ni ghtC. Two days agoD. Two days later10) My un cle went to last year. We have n't see n him .4 / 18A. since almost a yearB. from almost a year onC. after almost a yearD. si nee almost a year agohe went to bed.11) He was so tired that he fell asleepA. as ifB. eve n thoughC. ever sinceD. as soon as12) I knew nothing about the accide nt my friend told me yesterday.A. becauseB. sinceC. un tilD. after13) I did n't man age to do it you had expla ined how.A. un tilB. sinceC. whileD. after【Keys】1) C 2) A 3) B 4) B 5) A 6) D 7)B 8) C 9) B 10) D 11) D12) C 13) A条件状语从句条件状语从句用一般现在时表示将来。
引导条件状语从句的连词有：if 女口果；uni ess 除非，如果不；on con diti on that 条件是；as long as 只要2. 表示正面的条件用if “如果”。
If you don't look after young trees, they will die very quickly.If the museum charges for en try, a lot of people won't be able to visit it.3. 表示否定的条件用unless( =if.. . not) “除非，如果不”。
I shall not go to the cin ema unl ess I finish my homework before eight. 说明：if…not常可以用unless替代。
If you don't study hard, you will fail in the exam.You will fail in the exam unl ess you study hard.5 / 184. 表示使某事成为现实必要的条件用on condition that “条件是”，as long as，，口要”只要。