高中状语从句讲解

语法专题复习（四）状语从句讲解
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。

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．I fell asleep when he was doing his exercises .他正作练习时我睡着了。

（时间状语从句）
3．She always sings as she walks .她总是一边走一边唱。

（时间状语从句）4．I waited until he had finished his work .我等到他做完活。

（时间状语从句）
5．It was not long before he told me about this affair .不久，他就告诉我这件事。

（时间状语从句）
6．He has worked very hard since he entered the factory自从他进厂，工作一直很努力。

（时间状语从句）
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 ins tant, immediately , directly, no sooner … than, hardly …when, scarcely… wh en
2．地点状语从句
常用引导词：where
特殊引导词：wherever, anywhere, everywhere
3．原因状语从句
常用引导词：because, since, as, since
特殊引导词：seeing that, now that, in that, considering that, given that, conside ring that,?
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 that
5． 结果状语从句
常用引导词：so … that, such … that,
特殊引导词：such that, to the degree that, to the extent that, to such
a degree that,
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 ca se that, on condition that
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)，n o matter …，in spite of the fact that, while, whatever, whoever, wherever, wh enever, however, whichever
8．比较状语从句
常用引导词：as(同级比较), than(不同程度的比较)
特殊引导词：the more … the more … ; just as …，so…; A is to B what / as X is to Y; no … more than; not A so much as B
9．方式状语从句
常用引导词：as, as if, how 特殊引导词：the way
10特殊的
状语从句的简化
状语从句的省略
状语从句同时具备下列两个条件:①主句和从句的主语一致，或从句主语为it；②从句主要动词是be的某种形式。

从句中的主语和be动词常可省略。

例如：
When ( the museum is ) completed , the museum will be open to the public next year .
He’ll go to the seaside for his holiday if (it is ) possible.
另外，比较状语从句经常省略。

例如：
I’m taller than he (is tall ).
The higher the temperature (is), the greater the pressure (is ).
状语从句的"简化"现象常存在于以下五种状语从句中:
由if, unless等引导的条件状语从句;
②由although, though, even if / though等引导的让步状语从句;
③由when, while, as, before, after, until / till等引导的时间状语从句;
④由as, as if等引导的方式状语从句;
⑤由as, than等引导的比较状语从句。

下面针对这五种情形作一归纳。

If (it is) possible, he will help you out of the difficulty.如果可能的话,他会帮你摆脱困境。

You must attend the meeting unless (it is) inconvenient to you.除非情况对你来说不方便,否则你必须出席这次会议。

As (he was) young, he learned how to ride a bike.他小时候就学会了骑自行车。

Whenever (she is) free, she often goes shopping.她有空就去逛商店。

Work hard when (you are) young, or you'll regret.少壮不努力,老大徒伤悲。

While (he was) a you ng boy, he was always ready to help others.他在孩提时代就乐于助人。

Although (he is) doing his best in maths these days, he has still got no good marks.尽管近来他一直在学数学,但他仍然没有取得好成绩。

d.连词+过去分词
The concert was a great success than (it was) expected.这场音乐会出乎意料地取得了巨大成功。

He stood up as if (he were) to say something.当时他站起来好像要说什
He wouldn't solve the problem even if (he were) to take charge.即使他来负责,他也解决不了这个问题。

f. 连词+介词短语
She looked anxious as though (she was) in trouble.她看上去很焦急,好像遇到了麻烦。

He had mastered the English language before (he was) in the USA.他到美国之前就懂英语了。

tips:
只用as不用when或while的情况
1、用于表示同一个人的两种动作交替进行，指“一边…一边…”，
如：The girl sings as she goes to school.
2、表示两个同步发生的动作或行为
如：As time went by,she became more and more beautiful.
3、表示两个动作紧跟着发生，
如：As he was going out,it began to rain,
4、接在名词后面表示某一个年龄段时。

如：As a young man, he was active in sports.
连接词when,while,as的用法区别
1、while引导的时间状语从句的谓语动词必须是可持续的，而when引导的时间状语从句的谓语动词既可以可持续的，也可以是表短暂性动作的动词。

When\While he was eating his breakfast,he heard the door bell rang.
When I stopped my car,a man came up to me.(while不可用)
2、从句动作发生在主句动作之前时，只能用when 引导，不可用while\as, 如：When you have finished your work,you may have a rest
3、表示“随着……”,连词用as,不用when\while,
如：As the election approached,the violenve got worse.
4、如果主句表示的是短暂性的动作，从句用延续性动作的进行时态表示一段时间内正在进行的动作时，三者可互相交换使用。

如：When\While\As I was walking down the street,I came across an old friend of mine.
till,until和not…until用法
1、until\till引导时间状语从句用于肯定句中时，主句的动词时延续性动词，表示动作或状态一直持续到until\till所表示的时间，意为“某动作一直持续到某时间点才停止”，译为“直到…为止”。

You may stay here until the rain stops.
2、用于否定句时，主句谓语动词时非延续性动词，从句为肯定，意为“直到…才”，如：He wouldn’t go to bed till/until he had finished the work.
3、until 可以置于句首，till不行。

如：Until you told me , I had no idea for it.
4、not…untill句型中的强调和倒装说法：It is\was not until that…Not until+从句+助动词+主句。

t I had some idea for it.
Not until you told me did I hace any idea for it.
连接词since的用法
注：since的用法主要有两点：一是表示“自从…以来”，二是表示“既然”。

1、Since意思是“从那一刻开始”
如：He has studied very hard since he came to our school.
We have been missing them since they left here.
2、若since 引导的状语从句表示“从持续动作或状态结束时算起”。

如：I haven’t heard any noise since I slept. Sleep为持续性动词，sleep的动作结束时，即“醒来”时，译为“我醒后还未听到任何声响。

”
John is now with his parents in New York .It is already 3 years since he was a teacher.
3、若since其表示的时间的起点应从动作之时算起。

如：I haven’t heard from him since he has lived there.这里的has lived表示动作的持续性，时间的起点应从“开始居住”时算起，“自从他（开始）住在那儿，我就一直没有收到他的来信”
Since we have owned a car,we have gone camping every year.
4、句型it is +一段时间+since…与it has been +一段时间+since…意思相同，时
间的计算从since从句的动作完成或状态结束结束结束结束时算起。

It is 2 years since he left the country.
Before
1、it+（will/would）be +时间段+before…“过了（多长时间）才…”
It will be sometime before we know whether the drug takes effect or not.
2、it+（will/would）be not +时间段+before…“过不了多久就…。