初中英语知识点总结原因状语从句讲解
原因状语从句
连词有:because as since now that等
(1) 区分because, as, since, for
① because表示人们不知道的直接的原因或理由,着重点在从句,其所引导的从句,为全句句意的中心所在。通常用于回答why引出的疑问句,语气最强,除特别强调外,该从句一般位于主句后面,不能与so连用但是可以与so进行同义句转换。
I didnt go aboard with her because I couldnt afford it.
我没有和她一起出国是因为费用太高。
② as引导的原因状语从句所传递的通常是已知信息,从句多位于主句之前,表示双方那个已知的理由,如:
As I didnt know the way,I asked a policeman.
我不认识路,因而问警察。
③ since引导的原因状语从句多表示大家众所周知的理由,如:
Since traveling by air is much faster, they decided to take a plane.
既然乘飞机旅行快得多,他们就决定坐飞机。
④ for表示的理由是附加的或推断的,并非此原因,通常与主句用逗号隔开,不位于句首,如:
He must be not at home, for the telephone isnt answered.
用because, as, since, for 填空:
Well have to go to bed early ___________ well start off early tomorrow.
___________ you know all about it, tell me please.
____________ all the seats were taken, I had to stand.
He must be at work, __________ the light in his office is still on.
Lily didnt go to school ___________ she was ill.
=_________________________________________________________.
(4) now that引导的原因状语从句
Now that 因为;既然,通常可以和since换用。用来表示一种新的情况,再加以推论。如:
Now(that) you have passed your test, you can drive on your own.
你既已考试合格,就可以独自开车了。