now that?

now that是既然的意思,
这有两个例子，供楼主参考。
Now that if you want to go, go ahead whatever you want!
既然你想走，想干吗就干吗去吧！

now that he's turned angry,you'd better persuade him for a while
既然他生气了，你就去劝劝他。

既然
Now that you have come,just sit down.