You got me.
You've got me (there).
A：Do you know how to get there?
B：That's a good question. You've got me there.
Get it. 理解，懂得
You might want to slow down your lectures, I don't think the rest of the class gets it.
Get it together 振作起来
I hope he gets it together soon. His life is a mess.
Get sth. into one's head 相信某事是真实的
When are you going to get it into your head that you don’t need to worry about money? You’re rich now.
Get out of here! 得了吧（表示吃惊）
You just won the lottery? Get out of here!