看美剧学英语俚语：Blue in the face

Fannie

Blue in the face: Exhausted from anger, strain, or other great effort.(精疲力竭，却徒劳无功) For example, You can argue until you're blue in the face, but I refuse to go. This expression alludes to the bluish skin color resulting from lack of oxygen, which presumably might result from talking until one was breathless.

中文释义：blue in the face，这里的blue是指因为情绪激动、生气引起的脸色发青，有“脸红脖子粗”的意思。常见的用法是until you are blue in the face。它的字面意思是“直到脸变蓝色”，但实际要表达的是无论说什么、做什么（即使脸色都发青了），也是白费口舌、徒劳无功。 例如：You can explain it until you're blue in the face, but he will never understand.（你可以一遍遍地跟他解释，不过这是白费口舌，他不会理解的。）

今日看点：和“Blue”有关的表达
You look blue（你看起来很忧郁/很沮丧）
a blue joke（下流的笑话/荤段子）
a blue moon（千载难逢；不可能的事）