一、引导原因状语从句的从属连词

1.because 表示最强的因果关系

He distrusted me because I was new.他不信任我，因为我是新来的。

We couldn’t go out because it was too cold.因为天气太冷，我们不能外出。

2.as，since表示显而易见的或已为人们所知的原因

As you are sorry，I’ll forgive you.既然你悔悟了，我就原谅你。

As all the seats were full，he stood there.由于所有的座位都满了，他只好站在那里。

Since the weather is so bad，we have to delay our journey.

既然天气如此差，我们推迟一下行程吧。

3.now that 主要用于口语，强调人们已知的原因

Now that she has apologized，I am content.既然她已经道了歉，我也就满意了。

Now that you are busy，let me do it for you.既然你忙，就让我帮你做吧。

【提示】 since和now that引导的原因状语从句一般位于主句之前。

4.seeing （that），considering （that）表示“既然”

Seeing （that）he refused to help us，there’s no reason that we should now help him.

他既然曾经拒绝帮助我们，我们现在没有理由要去帮助他。

Considering （that）everybody is here，let’s begin our discussion.

既然大家都到了，我们就开始讨论吧。

5.in that常用于书面语中，表示“由于某种原因”

In that he is ill，he feels unable to do it.因为有病，他觉得做不了那件事。