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状语从句
在复合句中作状语的从句叫状语从句。

状语从句有时间、地点、原因、目的、结
果、条件、方式、比较、让步等种类。

一、时间状语从句
引导时间状语从句的连接词有: when, as, while, after, before, since, ever since, as soon as, once, till, until, whenever, no sooner…than, hardly/scarcely...when, the
moment/minute/instant/second, every time, each time, any time, the first time, next time, last time, all the time, by the time, directly, immediately, instantly等。

1.表示“一···就···”
的句型
1) as soon as/once
As soon as he arrives, I'll call you.他一到，我就给你打电话。

（as soon as 侧重时间或动
作先后衔接紧，而once侧重条件，表示“一旦...”
）
2) on doing sth/on one's + n.作时间状语
On arriving at the station, the thief was arrested.
一到达车站，这个小偷就被逮捕了。

On his arrival in Paris, he was recognized as a noble and thrown into prison. 他一到达巴
黎，就被认出是一个贵族，并被投入监狱。

3) no sooner ...than , hardly/scarcely...when
它们表“一…就”。

结构中的否定词放在句首时，主句要倒装。

（主句都用过去完成时，从句用一般过去时。

）
No sooner had he reached home than it began to rain.
他刚到家，天就开始下雨了。

Hardly/Scarcely had I entered the room when the phone rang.
我一进屋，电话就响了。

注意当no sooner, hardly, scarcely不放在句首时，主句不倒装，如：
I had no sooner reached the bus stop than the bus started.
我刚到车站，车就开走了。

I had scarcely（hardly）entered the room when the phone rang.
4）the moment, the instant, the minute, the second
The moment I saw him, I recognized him.
我一看见他，就认出了他。

We'll leave the minute you are ready.
你一准备好，我们就出发。

5)有些副词如：instantly, immediately, directly可用作连词，后接从句。

I left immediately the clock struck 5.
我刚走，钟就敲了五点。

2. when, while, as引导时间状语从句
1) when的用法
①when既可指时间点，也可指时间段（即：从句动词可以是短暂的也可是延续的）；主从句动作可同时也可先后发生。