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.
