各种状语从句的用法
1 时间状语从句：
（1）When引导的时间状语从句，表示主句谓语动词与从句谓语动词是同时发生的，或从句的动作发生在主句的动作稍前一点，when从句表示“一段”时间或“一点”时间。
When my cousin came yesterday , I was playing volleyhall.
昨天我表哥来时，我正在打排球。（came是一般过去时，表示时间点，was playing 表示一段时间，两个动作是同时发生的。）
我今天早上起床时，感到不舒服。（两个动作同时发生，都是一般过去时。）
when the air moves , it is called wind.
空气流动时，就产生风。（moves和katie goes to tokyois called 是同时发生。）
when he opened the door , he saw a girl sitting at the desk reading .
当他打开门时，他看见一个女孩正坐在书桌前看书。（opened发生在saw稍前一点，都用一般过去时。）
when I arrive home , I shall telephone you.
我到家时，将打电话告诉你。
(2) before引导的时间状语从句所表示的动作，发生在主句动作之后。如果强调主句动作的先完成，其谓语应用过去完成时，before引导的从句用一般过去时。如果不强调动作的先后，那么主句和从句的谓语用一般过去时。
he worked in Beijing before he came here.
他来这里之前在北京工作。（worked发生came在之前，但不强调先后，故用一般过去时。）
He had already worked for five hours continuously before he took a rest.
在他休息之前，他已连续不断的工作了五个小时。
（强调主句had worked 的在前，故用过去完成时。）
I saw him before he left.
他离开前我见过他。（saw比left稍前一些，但不强调两者的 前后，所以都用一般过去时。）
She was at school before she became a barber.
当理发师之前她在念书。（was发生在前，became发生在后，但不强调先后，故用一般过去时。）
shiwan英文姓名大全(3) after:用after引导的时间状语从句，所表示的动作发生在主句动作之前。如果强调动作的先后，after从句用过去完成时，主句用一般过去时，如果不强调先后而表示连续的动作，主句和从句用一般过去时。
after she finished her homework , she went to bed.确认
她完成了作业就去睡觉了。（表示一个动作接着一个动作，用一般过去时。）
This morning he got up early . he put on his clothes , washed his face , brushed his teeth and then had his breakfast.
After he had had breakfast he went to school.
（got, put on , washed , brushed ,had 都用一般过去时，因为是连续的动作。Had had 用过去完成时，因强调“吃饱”发生在went 之前。）
I shall write to you after I arrive in shanghai .
到上海后我将给你写信。（arrive这个动作先与shall write ,arrive 是以现在时代替将来时，不可改为shall arrive ）
(4) while:用while引导的时间状语从句，强调主句的动作和从句的动作 在某一时间内同时发生，意为“在。。。期间，在。。。过程中“。while引导的时间状语从句只能表示一段时间，所以必须是可延续的动作。不能表示时间的点，所以不可也非延续性动词连用。
while they were having supper , I came to their home.
正当他们在吃饭时，我来到他们家。（were having是过去进行的动作，came是过去的一点动作。）
Father took care of the child while his wife was away.
妻子不在家时，父亲照顾小孩。（took care和was 都是一半过去时，表示同时发生。）
I was doing my homework while my mother was cooking.
商务英语论文我母亲在做饭时，我在做家庭作业。（was doing 和was cooking两个动作同时发生。）
(5)until(till):till和 until都表示“直到“，两个词常互换使用，用法有以下两种：
（1）如果主句谓语动词为非延续性，如come ,go ,enter ,return ,start ,reach ,finish ,stop 等，主句用否定式，从句用肯定式，如结构，意为“直到。。。。才“或”在。。。之前不“。
she won’t go to bed , until / till her mother returns.
直到她母亲回来她才睡。（或“她母亲回来之前她不睡“。）
They didn’t leave the classroom until/till they finished their homework.
他们完成了家庭作业才离开教室。（或“在完成作业之前，他们没有离开教室“。）
We won’t start until peter comes.
要等到彼得来了，我们才开始。
（2）如果主句谓语为延续性动词，如stay ,wait ,read 等，主句和从句用肯定式，意为“直到。。。“。
I waited until/till she came back.
grips>vegetable是可数名词吗我一直等到她回来。
The children were playing in the playing until/till it was very dark.
汉文翻译
孩子们在操场上一直玩到了天很黑。
He ran until he was breathless.
他一直跑道气喘嘘嘘。
(6) as:用as引导的时间状语从句表示“当。。。时“，”一边。。。。一边。。。。“，主句的动作和从句的动作通红司发生，as引导的时间状语从句既可表示一段时间（用延续性动词），也可以表示某一个时间点（用非延续性动词）
as we were walking in the street , it began to rain.
正当我们在街上走，天开始下起了雨。
I gave he the letter as she came out of the classroom.
当她走出教室时，我把信给了她。
She sang as she wet along.
她一边走一边唱歌。
ieas
When he was a child.
While he was a child. He lived in Beijing .
As he was a child.
当他是个小孩时，他住在北京。（可见as有时可与when和while换用）
(7)since:引导的时间状语从句意为“自。。。以来“。从句的动词表示动作的起点，用一般过去时。主句中的动词表示动作的延续情况，一般要用现在完成时，但要注意两点：
elife什么意思（1）如果主句中的动词是表示状态，而不是动作，可用一般现在时。
（2）在某种特定的上下文中，主句要用过去完成时，而不用现在完成时。
five years have pasd since he began his work here.
自从他开始在这里工作，已经过了五年。
It is thirty years since I taught English .
我教英语已三十年了。
She said she had worked in she university for three years since she returned from the USA.
她说自从美国回来后，她在大学工作已三年了。
He has lived here so long since he came.
他来以后，已经在这住这么久了。
I haven’t heard from her since she left Beijing .
她离开北京以后，我再未收到过她的信。
（8）no sooner….than ,hardly when ,scarcely when 表示“刚。。。。就。。。。“，”一。。。就。。。“。主句的动作先发生用过去完成时，从句用一般过去时。如果这些连接词置与句首，就要用半倒装次序，即把助动词had放在主语前。如果不放在句首，即不必倒装。
No sooner had she heard the news than she fainted.
She had no sooner heard the news than she fainted.
她一听到这个消息就晕了。
Hardly had they started to work when the trouble began.
