时间状语从句和让步状语从句

Unit 5 Warm-up & Lesson 1，Unit 5 Lesson 2

【归纳】

★时间状语从句

1. 由when, while, as引导的时间状语从句

(1) when引导时间状语从句表示"当......的时候"，从句谓语动词可以是延续性动词也可以是短暂性动词。如：

I went there when I was a child.

He was quite shocked when I told him the news.

when还可以表示突然发生某事，常译为"正在......忽然......"。如：

I was doing my homework when there was a big noise outside.

(2) while引导时间状语从句表示"当......的时候"，从句中的谓语动词一般是延续性动词。如：

While Mary was writing a letter, the children were playing outside.

I can learn while I work.

(3) as引导时间状语从句表示"当......的时候"，强调主、从句的两个动作几乎同时发生，或者一个动作随着另一个动作的变化而变化。如：

As I was going out, it began to rain.

"I'll call you at nine," he said as he left her.

He gets more attractive as he gets older.

2. until, till引导时间状语从句时，在肯定句中表示"做某事直到某时"，在否定句中表示"直到某时才做某事"。如：

　We waited until it got dark.

　I didn't have a personal computer till I was 18.

3. as soon as, directly, immediately, the moment / instant, hardly ... when, no sooner ... than等引导时间状语从句时，表示"一......就......"。如：

As soon as / Directly / Immediately / The moment / The instant I hear the news, I will let you know.

　We had hardly sat down at the table, when the phone rang.

He had no sooner got home than he began to cook.