1.引起原因状语从句的连词：
1) because 因为：
I study English because it is useful for my work.
我学英语因为它对我的工追有好处。
She is in bed beouse she is ill.
她没起床因为她病了。
Because they lived on the edge of the Persian Empire, they were ruled by the king of Persia .
因为他们住在波斯帝国边上，他们由波斯国王统治。
2) as 因为，由于：
As he wasn't ready he didn't come with us.
由于他没准备好，他没和我们一块儿来。
We couldn't go to school as life was very hard then.
我们没能上学，因为那时生活很苦。
As you can't drive, you must go by bus.
由于你不能开车，你得坐公共汽车去。
3) since 既然，由于：
Since you don't want to go, we won't force you to.
既然你不想去我们就不勉强你了。
We had to put the meeting off since so many people were absent.
由于很多人没来，会议只好延期。
Yon may take this book since I have read it.
这本书你可以拿去看，因为我已经看过了。
4) now (that)既然已经：
Now that you are all back, we'd better start the work right away.
你们既然都回来了，我们最好马上就干起来。
Now(that) you are well again, you can travel.
既然你已痊愈，你就可以旅行了。
My mother runs it now that she and Dad are divorced.
现在妈和爸离婚了，商店就由妈经营。
5) seeing that 由于，考虑到：
Seeing that nobody was very enthusiastic about it, they decided to cancel the trip.
由于没有人有此热情，他们决定取消这次远足。
He has done well to pass his exams, seeing that he has been ill a lot.
考虑到他多次生病，他考试能及格就很不错了。
