八种状语从句

八种状语从句

状语从句在句中作状语，修饰主句中的动词、形容词和副词等。按其作用和意义可分为时间、原因、目的、结果、条件、让步、方式、比较八种。下面对这八种从句的要点加以总结。

一、各类状语从句的引导词及易混词的区别。

1. 时间状语从句

1) 引导词

（1）表示“当……时候”：when, while, as, whenever

（2）表示“一……就……”：as soon as

（3）其它：after, before, since, until, by the time

Whenever he comes, he brings a friend. 他每次来都带个朋友。

I want to see him as soon as he arrives. 他一来我就要见他。

I went to bed after I finished my homework. 我做完家庭作业之后才睡觉。

2) 易混引导词when, while, as 的区别

when既可指“时间点”，与瞬时动词连用，也可指“时间段”，与延续性动词连用（这时可与while互换）。如：

When he came in, his mother was cooking. 他进来时，他妈妈正在烧饭。

When（While）we were at school, we went to the library every day. 我们在校求学时，每天都到图书馆去。

while 只表示时间段，因此while从句的谓语动词要用延续性动词。

Please don' t talk so loud while others are talking. 别人在工作时，切勿大声讲话。

as 与when 用法相似，但着重强调主句动作与从句动作同时发生，有“随着……”或“一边……一边……”之意。

She sang as she went along. 她边走边唱。

As you get older, you get more knowledge.随着年龄的增长，你获得的知识就越多。

2. 原因状语从句

原因状语从句由because, as, since 引导词。他们的区别如下：

because 用于表示直接原因，用于回答why提出的问题，语气最强。

as 由于说明原因，语气较弱，着重点在主句，常译成“由于”。

since表示显然的或已知的理由或事实，常译成“既然”。

Water is very important because we can' t live without it. 水非常重要，因为没有它我们就不能生存。

He didn't come yesterday as his mother was ill. 他昨天没来，因为他母亲病了。

I' ll do it for you since you are busy. 既然你忙，我来替你做吧。

Now that Mr. Smith is well again, he can travel. 史密斯先生病好了，他可以旅行了。

It must have rained last night, for the ground is wet this morning.今早地还是湿的，昨晚准是下雨了。

3. 目的状语从句

目的状语从句的引导词有so that, in order that 。从句中常有情态动词can, could, may, might, would, should等。

Finish this so that you can start another. 你把这个做完, 好开始另一件事。

He set out early in order that he might arrive in time. 为了能按时到达，他很早就出发了。

4. 结果状语从句

结果状语从句由such...that, so... that , so that引导。这里要注意以下两点：

1) such 是形容词，修饰名词；so 是副词，修饰形容词或副词。但当名词被表示“多”、“少”的many, much, few, little修饰时，也要用so。

He is such a lovely boy that we all like him. 他是一个如此可爱的男孩，我们都喜欢他。

It was so cold that the twins couldn't go out. 天气这样冷，双生姊妹不能出门。

She made so few mistakes in the exam that the teacher praised her for it. 她在考试中几乎没犯错误，老师为此而表扬了她。

2）单数可数名词在有形容词修饰的情况下，既可用such 也可用so 修饰，但词序不同。如：such a cold day= so cold a day。

5. 条件状语从句

条件状语从句的引导词有if, unless。条件状语从句也用一般现在时表示将来时。

As long as I am alive, I' ll go on studying. 只要我活着，我就要学习。

We spoke in whispers for fear that we might wake the baby. 我们轻声谈话，以免吵醒婴儿。

6.让步状语从句

让步状语从句的引导词有though/although。

Although/Though he is in poor health, he works hard. 虽然他身体不好，但是工作努力。