Xiaobaitu Help Please

Hi Xiaobaitu,

My girlfriend is currently with F-1 visa. I am green card holder.

My questions are:

(1) if we get married, can she still maintain her F-1 visa?
(2) If she goes back China, can she still come back US with F-1 visa?
(2) Can I apply GC for her? Or I have to be a citizen to do that?

Thanks a lot

Yin