英语总结（一）——时间状语从句

英语高亮注意（

时间状语从句

用法

用来在句中充当时间状语成分。

连接词

when, while, as, after, before, since, until/not...until,
once, immediately, directly, instantly,
as sonn as, by the time, the moment, the minute,
no sooner ... than, hardly ... when 等。

简单例句

When you think you know nothing, then you begin to know something.
Strike while the iron is hot.

主要时态：

主现从不限；主过从过；主将从现（重点）；主祈从现；主情从现。

要点

while, when, as比较

when 引导从句的谓语一般是瞬间性动词，泛用性较强。从句动作和主句动作可以同时发生，也可以先后发生。若是暗示一种规律，那么也用when。
while 引导从句的谓语是延续性动词，强调某一时间段内主从句动作同时发生，相当于during the time that...。可以表对比（并列连词）。
as 常用来表示"一边...一边..."；还可以用来说明两种正在发展或变化着的情况，有“随着”的意思，表示时间的推移。

- 例句
It’s cold when it snows.
I was playing games when he came in.
While/As she was studying, I was playing games.
While we were talking, she came in.
She sang as she went along.
As she grew older, she kept more to herself.

when的几种句型

(be about to do)/(on the point of doing) when ... 刚要做...时突然...
was/were doing when ... 正在做...时突然...
have/has done when ... 做完了...时突然...

before的几种用法

It won't be ... before ... 用不了多久就...
It will be ... before ... 还要过多久才...
It wasn't be ... before ... 没过多长时间就...
It was be ... before ... 过了多长时间以后才...

- 例句
It won't be long before the end of the class.要不了多久就下课了。
It will be a long time for one to gain his own success.一个人要取得成功要很长时间。
It wasn't long before the couple met again.这对夫妇没过多久就相见了。
It was long before they found their son.过了很久后，他们才找到他们的儿子。

until要点

强调句中多用until而非till, 如果主句谓语是瞬间动词，那么要用not...until. 如果主句动词时延续性动词，那么均可，且常用肯定形式。till不可置句首，until可以。

- 例句
Please wait until I arrived.
I didn't go to bed until(till) my father came back.
It was not until the meeting was over that he began to teach me English.
I worked until he came back. 我工作直到他回来为止。
I didn't work until he came back.我直到他回来才开始工作。

since要点

一般情况下，从句中用一般过去式，主句谓语动词用现在完成时。
1）since引导的状语从句的谓语动词是持续性动词或表示状态动词（如live，stay，study，learn，smoke，be等）的过去时，则从句表示的时间是“从动作或状态的完成或结束时算起”。
2）since引导的状语从句的谓语动词为持续性动词或表示状态动词（如live，stay，study，learn，smoke，be等）的现在完成时，那么since所表示的时间是“从动作开始的那一时刻起”，翻译时按字面的意思理解即可。

- 例句
I have been in Beijing since you left. 自从你离开以来，我一直在北京了。
It is four years since my sister lived in Beijing. 我妹妹不在北京住有四年了。
She has never come to see me since I have lived in the city.自从我住到城里，她就一直不来看我。
I haven’t heard any noise since I slept. 我醒后还未听到任何声音。
Do you know how long it's been since I've grabbed a spoon?你知道自从我拿起勺子多久了吗？

as soon as要点

类似词汇：once, immediately, directly, instantly, the moment, the minute, the instant
强调动作的紧随，注意区分after和when. 即as soon as主句动作紧跟从句动作。

- 例句
As soon as I reach Canada, I will ring you up. 我一到加拿大，就给你来电话。

by the time要点

如果从句中谓语动词一般过去时，那么主句中的动作常用过去完成时。
如果从句中谓语动词是一般现在时或者现在完成时（表将来），那么主句中动作常用将来完成时。
如果主句中动作不强调已经完成，那么根据时态选择。

- 例句
By the time I got to the station, the train had already gone.
By the time I graduate next year, I will have lived here for 5 years.
By the time he went abroad, he was 14 years old.

几种倒装

no sooner ... than, hardly when, scarcely ... when结构中主句用过去完成时，从句一般用一般过去时。
且当这些表示否定意义的词或者短语在句首，主句部分倒装。