《英语语法大全》（主编 约翰 辛克莱）第437页8.18

主句说明某事由于新情况引起的状况，用从句对新情况予以说明。

从句用“now”或“now that”引出。

I feel better now I’ve talked to you.

He soon discovered how much faster he could travel now that he was alone.

《COBUILD英汉双解词典》（主编 约翰 辛克莱）第1317页now词条9

now that or now is used when you want to say that the effect of something that has happened is that something else takes place. 既然；由于

Now that she’s found him, she’ll never let him go.

她既然找到了也就决不会让他走了。

Now that I am old, I can read all the books I’ve always meant to read.

我已经老了，我可以看我一直想要看的所有那些书了。

I like him a lot now he’s older. 我非常喜欢他，因为他现在年龄大了。

《朗文A-Z英语语法大全》第384页now词条

now (that)是从属连接词，既表示时间又表示原因。

Let’s have a drink, now (that) you’re here. (=because you area nowhere).

既然你来了，咱们就喝一杯吧。

Now (that) I’ve learned to drive, I will be able to go to work by car.

现在我已经学会开车，可以开车上班了。

2016年12月8日