状语从句用法详解
定义：在复合句中作状语的从句
功能：状语从句在主从复合句中修饰主句中的动词，形容词或副词，或整个主句
分类：按意义可分为时间、地点、原因、目的、结果、条件、方式、比较、让步等状语从句。从句的位置放在句首，也可放在句末。放在句首时，从句后面常用一个逗号，放在句末时，从句前一般不用逗号。
一、时间状语从句
when, while, as, before, after, since, until (till) , once , as soon as, the moment, the minute, immediately, directly, each/every time, the first time, the last time, next time, by the time, whenever等。
Every/Each time I was in trouble, he would come to my help.
I thought her nice and honest the first time I met her.
A. when, while, as的区别：
1)when引导从句时，主从句的动作有先有后，也可以同时进行,从句的动作可以是持续性的，也可以是短暂的。如：
When I got to the airport, the plane had already taken off.
When I lived there, I ud to go to the aside on Sundays.
When the movie ended, the people went back.
2)while侧重主句的动作发生在从句的时间之间，且从句的动词必须是持续性的。
While we were chatting ,she was looking at the time table on the wall．
3)as引导从句时侧重主从句动作同时或几乎同时进行，从句的动作可以是持续性的，也可以是短暂的。
as表示 一边……一边……，强调从句和主句中两个动作交替进行或同步进行。as表示随着，此用法不用when或while替代。
Sometimes I watch TV as I am having breakfast．
He looked behind from time to time as he went.
As spring warms the earth, al flowers begin to bloom.
其它用法: 1．when
＊并列连词when常用与以下句型中, when只能跟在前一分句之后。
①…was/were doing…when(suddenly)…（正在做…突然）
②…was/were about to do…when…（刚要做…突然）
③…was/were on the point of doing…when…(刚要做…突然)
④…had just done…when….(刚一…就)
⑤Hardly/Scarcely had…done…when…(刚一…就)
He was about to go to bed when the doorbell rang.
房屋买卖合同编号
They were watching the World Cup when suddenly the lights went out.
They had just arrived home when it began to rain.
Hardly had I stood up when he said hello to me.
＊有时when表示虽然，尽管的含义，相当于怎么钓螃蟹although或since。
He walks when he might take a taxi.
扁蓄草图片
How can you hope for mercy yourlf when you show none .
＊如果when引导的时间状语从句的主语与主句主语相同， 而从句的谓语又是be动词时， 那么从句中的主语和be可以省略；
When (you are) in trouble, ask her for help.
＊当when引导的时间状语从句的主语与主句主语相同时， 往往还可以用“when＋分词”的形式替代该状语从句。
When I came into the room(=When coming into the room), I found him lying there asleep.
2．while
＊while有时可以作并列连词，表示对比，可译成……而……。
I am fond of English while he likes math.
We slept while the captain kept watch.
＊while有时可引导让步状语从句，意思是虽然。
While they love the children, they are strict with them.
1. I had just stepped out of the bathroom and was busily drying mylf with a towel ____ I heard the steps.
A. while B. when C. since D. after
2. — I’m going to the post office. — ____ you’re there, can you get me some stamps?
放荡教师在线阅读A. As B. While C. Becau D. If
3.____ the days went on, the weather got wor.
A. With B. Since C. While D. As
4. Tom ____ into the hou when no one ____.
A. slipped; was looking B. had slipped; looked爱情电影排行榜 C. slipped; had looked D. was slipping; looked
5. I ____ along the street looking for a place to park when the accident ____.
A. went; was occurring B. went; occurred C. was going; occurred D. was going; had occurred
B. before, after
1．before表示在一段时间之前。
You must first learn to walk before you try to run.
He had learned English for three years before he went to London.
She didn’t go out before she finished her homework.她把作业做完才出去的。(=not……until……)
提示： before 从句往往带有否定的含义，常译为：还没等到….就….邵小利；还没来得及…就……趁着还没……就……。作此意时，从句中常见情态动词can/ could。
He ran off before I could stop him.
The man hung up the phone before I could answer it.
He almost knocked me down before he saw me.
Before I could get in a word, he measured me.
扫描机【必背】before 常用句型
①It will be + 时间段 + before + 一般现在时：要等多久才…….
It will be five years before we meet again. 五年以后我们才能再见。
②It won’t be long before+ 一般现在时：等不了多久就会……
It will not be long before you regret what you have done.
③It was +时间段+before +一般过去时：等了多久就……
It was minutes before the police arrived.
④It wasn’t long before+ 一般过去时：没等多久就……
It was not long before I realized I was wrong.
【对比】
It is/ has been +时间段+since +一般过去时： 自从……以来到现在已经有多长时间
It is three years since the war broke out.
2．after
after表在一段时间之后。
The sun came out soon after the storm stopped.
1.He was told that it would be at least three more months ____ he could recover and return to work.
A. when B. before C. since D. that
2.It was some time ____ we realized the truth.
A. when B. until C. since D. before
3.— How long do you think it will be ____ China nds the cond manned spaceship to the moon?
— Perhaps two or three years.
安卓手机怎么root
