编辑:
2015-12-11
这三个连词都可引导时间状语从句,但用法有所不同。
1) 当某事正在进行的时候,又发生了另一件事。While, when, as 都可用来引导表示“背景”的时间状语从句。例如:
As/When/While I was walking down the street I noticed a police car.
2) 当两个长动作同时进行的时候,最常用的是while。例如:
While mother was cooking lunch, I was doing my homework.
3) 当两个动作都表示发展变化的情况时,最常用的是as。例如:
As children get older, they become more and more interested in things around them.
4) 当两个短动作同时发生时,或表示“一边…一边…”时,最常用as。例如:
Just as he caught the fly, he gave a loud cry.
She looked behind from time to time as she went
5) 当从句的动作先于主句的动作时,通常用when。例如:
When he finished his work, he took a short rest.
6) 当从句是瞬间动作,主句是延续性动作时,通常用when。例如:
When John arrived I was cooking lunch.
(2)as, because, since , for
这四个词都可表原因,但用法有区别。
1) 如果原因构成句子的最主要部分,一般用because。因此,because引导的从句往往放在句末。例如:
I stayed at home because it rained.
---Why aren’t you going?
---Because I don’t want to.
2) 如果原因已被人们所知,或不如句子的其它部分重要,就用as或since。Since比as稍微正式一点。As和since 引导的从句一般放在句子的开头。例如:
As he wasn’t ready, we left without him.
Since I have no money, I can’t buy any food.
3) for用来补充说明一种理由,因此,for引导的从句几乎可以放在括号里。For引导的句子不放在句子的开头。例如:
I decided to stop and have lunch----for I was feeling quite hungry.
(3)if, whether
if和whether都可作“是否”讲,在引导宾与从句是一般可互换。例如:
I wonder whether (if) you still study in that school.
I don’t know whether (if) he likes that film.
标签:中考英语考点
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