如果你坚持做某事直到you are blue in the face，意思就是你花很长时间做一件事情，做到脸都发青了也没用，不会成功。

Martin argued with his mother until he was blue in the face, but she still made him wash the dishes.
You can walk up and down the high street until you are blue in the face, but you won’t find a shop selling leather shoes as cool or as cheap as these!
值得注意的是，还有一个与blue相关的短语“once in a blue moon”。指的是“千载难逢的，罕见的，难得的”。

I only eat red meat once in a blue moon these days. You never know what’s in your burgers, especially after the horsemeat scandal.