在SAT阅读突破难句三中我们已经学过了名词性从句和定语从句，那么接下来百利天下小编带领大家学习的是SAT阅读突破难句四：时间状语从句，大家可以结合老师的视频讲解，帮助自己更好的学习。
一.辨别句子
1. What he wants is a book.(主语从句)
2.1t is so nice that we can learn this grammar point together. (主语从句)
3. I'm so glad that I can make friends with you.(宾语从句)
4. This is why he did it. (表语从句)
5. Do you agree to the suggestion that we (should) have a trip in Tibet? (同位语从句)
6. That he wants a book is certain.(主语从句)
7. I suggested just now we (should) take part in this activity. (宾语从句)
8. Whether you like him or not doesn’t matter too much. (主语从句)
9. He doesn't know whether you can sing it well. (宾语从句)
10. The problem is whether you can sing it well. (表语从句)
11. The problem whether it is right or wrong has not been decided. (同位语从句)
12. Please tell me who your monitor is. (宾语从句)
13. The girl who is sitting in the corner is a singer. (定语从句)
14. The woman they wanted to visit is a teacher. (定语从句，省略了现行词who)
15. This is a time when adequate food resources will be assured. (定语从句)
二.状语从句
定义：在复合句中由从句表示的状语称作状语从句，它可以用来修饰谓语或是整个句子。状语从句的作用相当于一个副词。
状语从句的位置比较灵活，有时可以放于句首，有时可以置于句末。状语从句位于句首时,其后常用逗号与后面的句子隔幵。
状语从句的分类：状语从句可以根据其用途分为
(1)时间状语从句、(2)地点状语从句、(3)原因状语从句、(4)结果状语从句，(5)目的状语从句、(6)条件状语从句、(7)让步状语从句、(8)比较状语从句，(9)方式状语从句。
(一)时间状语从句
引导时间状语从句的连词有：
when, while, as, the moment, before, after, till, until, since, as soon as 等。
1. 连接词when的用法小结
(1)when引导的时间状语从句的谓语动词，可以是可延续，也可以是表短暂性动作的动词(非延续性)。
如：When the film ended, the people went back.
When I lived there, I used to go to the seashore.
(2)可用作并列连词，其意义为"在那时, 在这时”，相当于 and at this/that time常用于下列句式：(刚要......这时突然……)
Someone + was doing / was about to do/had just done/Sb. was on the point of doing…..+ when
比如：I was walking along the street, when I met him.
I was about to fall asleep when my sister come in.
(3)还可以表示原因“既然“，相当于since，considering that
如：Why do you walk when you have a car?
2. while的用法小结
(1) while引导时间状语从句,从句的动作必须是持续性的,在..... 期间，往往指一段时间.如：
While we were talking, he came in.
Please don't talk so loud while others are working.
(2) while作为并列连词，意为“而，却"，侧重主句动作和从句 动作相对比.
We are cleaning the classroom while they are playing the football.
(3)while可表示尽管引导让步状语从句，相当于although，放在句首位置。
while含义：
While I was walking down the street, I came across an old friend.
He likes pop music, while I am fond of folk music.
While I really don't like art, I find his work impressive.
While there is life there is hope.
3. 连接词when, while, as的用法区别
(1)while引导的时间状语从句的谓语动词必须是可延续的，而when引导的时间状语从句的谓语动词是可延续的，也可以是表短暂性动作的动词。
When/While he was eating his breakfast, he heard the doorbell ring.
When I stopped my car, a man came up to me.
(不可延续，短暂性如词，只可以用when不可用while)
(2)表示“随着......“ ，连词用as,不用when或while
As the day went on, the weather got worse.
(3)如果主句表示的是短暂动作，而从句用延续性动作的逬行时态表示在一段时间内正在进行的动作时，when, while与as可 互换使用。
When/While/As I was walking down the street，I came across an old friend of mine.
(4)从句动作发生在主句动作之前时，只能用when引导这个从句，不可用as或while
When you have finished your work, you may have a rest.
When the children had gone to bed，she began to prepare her lessons. (这个时候的when= after)
4. 连接词before和since的小结
(1)Before的用法：
We had sailed four days and four nights before we saw land.
Before从句中谓语不用否定式
如：Before they reached the station, the train had gone.
(2)Since的用法：
it is/ has been+段时间+since从句中，时间的计算从since从句的动作完成或状态结束时算起。
It is three years since she was in our class. 她离开我们班有三年了。
It is three years since he lived here. 他不住这儿有三年了。
比较：
It is three years since I smoked a cigar.
It is three years since I began to smoke.
5. “一...就"的用法
(1)as soon as “一...就" ”刚…就"
我一到达上海就给你打电话。(时态)
I will call you as soon as I arrive in Shanghai.
时态要求：从句以一般现在时代替将来时
(2)No sooner than “一…就…”
He had no sooner arrived than he went away again.
前部分一般用过去完成时，后部分用过去时
(3)no sooner…than , hardly/scarcely... when. . etc.(—…就…}
注意:用于句首时应引起部分倒装
No sooner had he arrived than he went away again..
6. till、until的用法小结
till表示主句动词是持续性动作，常用肯定式，表示"直到…为止".亦可用until替換
Until表示主句动词是瞬间动词，常用否定式，表示"直到... 才""在...以前不",从句放在句首表示强调
We waited till (until) he came back.
She didn't stop working until eleven o'clock.
更多内容查看点击：SAT阅读突破难句三：名词性从句和定语从句
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