不懂就不懂用英语怎么说（我完全不懂用英语怎么说）

I'm short on cash! 我缺钱!

I've got the blues! 我很郁闷!

　　If I were you...=if I were in your shoes 如果我是你...

It kills my eyes! 太好看了!

It's Greek to me! 我完全不懂!