Examples
nǐ你jì rán既然yǐ jīng已经zhī dào知道le了，hái还wèn问shén me什么？
你既然已经知道了，还问什么？
If you already know, why are you still asking?
既然雨已经停了,我们可以回家了.
Now that it has stopped raining, we can go home.
既然你在这里,那我们就开始吧。
As long as you are here, we might as well begin.