【上期回顾】

【本期内容】

一、内容纲要

二、内容简述

（一）定义

用表示时间的连词连接一个句子，充当另一个句子的状语，这个句子就叫做时间状语从句。

常用来连接时间状语从句的连词有：when, while, as; before, after; till, until, since; 表“一...就...”的句型；every/each time, by the time。

（二）when、while与as

三者都可以表示“当...时候”，其区别在于：

1、when所在的从句，以及其主句的谓语动词，可以是瞬间动词，也可以是持续动词，如：

When he came yesterday, she told him the bad news.

When she was working in the garden, her son woke up.

【注意】

当基于现在时间表将来时，其主从句的谓语动词遵循“主将从现”的用法，如：

When she arrives tomorrow, I will give her the book.

2、while所在的从句的谓语动词必须是持续动词，或表状态的静态动词，其主句谓语动词可以是瞬间动词或持续动词。如：

While he was away from home, his neighbour took care of his garden.

While I was reading in the living room, my wife was writing her novel in the study.

While my son was sleeping, my wife came home.

3、as表示“一边...，一边...；正当；随着”，其所在的从句以及主句谓语动词可以是瞬间动词或持续动词。如：

As I was growing vegetables, my daughter watered them.

As the sun rose, the fog disappeared.

（三）before与after

before表“在...之前”，after表“在...之后”。如：

Before he came back, she had already left.

After she had already left, he came back.（四）till、until与since

till表示“直到...时候”；until也表示“直到...时候”，常与not连用，表示“直到...时候才...”；since表示“自从...时候以来”。如：

I will stay here till/until she comes back.

He did not go home until he had finished his work.

She has lived here since she was born.

（五）表“一...就...”的句型

常见的有：as soon as, hardly...when..., no sooner...than..., the minute/second/instant/moment...。如：

As soon as he arrived there, he called me.

He had hardly arrived there when he called me.

He had no sooner arrived there than he called me.

The minute/second/instant/moment he had arrived there, he called me.

（六）every/each time与by the time

every/each time表示“每当...”，后面直接接从句。by the time表示“到...时候为止”，后面直接接从句。如：

Every/each time he comes, he will bring me some flowers.

By the time she comes back, I will have finished the work.

By the time she came back, I had finished the work.