状语从句

状语从句在句中作状语，说明时间、原因、条件、目的、结果、让步、比较等。

16.1 时间状语从句

常见引导词：

when, while, as, before, after, until, since, as soon as

例句：

When I arrived, he was reading.
我到的时候，他正在读书。

I will call you as soon as I get home.
我一到家就给你打电话。

在时间状语从句中，若主句是将来意义，从句常用一般现在时表示将来。

正确：I will call you when I arrive.
错误：I will call you when I will arrive.

16.2 条件状语从句

常见引导词：

if, unless, as long as, once, provided that

例句：

If it rains tomorrow, we will stay at home.
如果明天下雨，我们就待在家里。

You will fail unless you work hard.
除非你努力，否则你会失败。

条件状语从句同样常用一般现在时表示将来。

If he comes tomorrow, I will tell him.

16.3 原因状语从句

because, since, as

because 语气最直接，回答“为什么”。

I stayed home because I was sick.
我待在家里，因为我病了。

since/as 常表示已知原因，语气较弱。

Since everyone is here, let's begin.
既然大家都到了，我们开始吧。

16.4 让步状语从句

although, though, even though, even if, while

例句：

Although it was raining, they went out.
虽然下雨，他们还是出去了。

Even if I fail, I will try again.
即使失败，我也会再试。

16.5 目的和结果状语从句

目的：

so that
in order that

例句：

He spoke slowly so that everyone could understand him.
他说得很慢，以便每个人都能听懂。

结果：

so...that
such...that

例句：

He was so tired that he fell asleep quickly.
他太累了，很快就睡着了。

It was such a good movie that I watched it twice.
这电影太好了，我看了两遍。