2018-2019学年北师大版高中英语必修2学案Unit5 GRAMMAR 时间状语从句和让步状语从句

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. 注：当hardly或no sooner位于句首时，主、谓语要进行部分倒装。如： Hardly had we got into the country when it began to snow. No sooner had I started playing tennis outside than it started raining. 4. since, ever since引导时间状语从句时，表示“自从……以来”，其主句多用完成时。如： I’ve been very busy since I came back from holiday. He has been living in Leeds ever since he moved there 3 years ago. 5. 引导时间状语从句的词或短语还有：after, before, every time, the first  / second ...  / last time, by the time等。如： Every time I come, he is reading. By the time he was taken to the hospital he was nearly dead. ★让步状语从句  1. though, although, even if, even though引导让步状语从句，表示“即使，虽然，尽管”。注：though和although引导让步状语从句时，不与but连用，但可与yet, still等连用。如： Though / Although he’ s got a good job now, he still complains. Even if / Even though it is difficult, we shall still do it. 2. as引导让步状语从句时，常将形容词、副词、名词或实义动词提到句首，构成倒装。though也可用于此结构。如： Old as / though I a