a black eye眼睛瘀青；汙點。a black eye是指「被打得瘀青所造成的黑眼圈"，如果要描寫睡眠不足造成的黑眼圈，請用dark circles。另外，由於眼睛周圍的瘀青很明顯，因此a black eye也被用來比喻不光彩的事。
看看老外聊天時怎麼用a black eye：
Jenny: Do you think Howard can serve another term as state governor?
Kevin: I don't know. He has to win ack people's trust.
Jenny: Are you talking about the homeless issue?
Kevin: Yes. The growing number of homeless folks is a black eye for him.
Jenny: That's true.
珍妮：你認為霍華德能順利連任州長嗎？
凱文：不知道，他必須贏回人民的信任。
Ee：你是指遊民問題嗎？
凱文：是啊，遊民人數的暴漲是他的汙點。
珍妮：這倒是。
a black eye例句精選：
He got into a fight and has a black eye.
他加入了打鬥，一隻眼睛被打青了。
After the fight one of the boxers had a black eye.
對打之後，一個拳擊運動員的眼睛被打青了。
The school has gotten a black eye from this incident.
這次事故損害了學校的聲譽。
dark circles例句精選：
I have always had dark circles and have a few fine lines.
我總是有黑眼圈，還有一些細紋。
She was looking strained and had dark circles beneath her eyes.
她看上去神情緊張，眼圈也變黑了。
Then how can I cover up my dark circles with makeup?
那我又該如何用化妝品遮我的黑眼圈呢？
Put cucumber or tomato slices over your eyes to get rid off the dark circles.
把黃瓜或西紅柿的切片放在眼睛上，這樣可以去除黑眼圈。
拓展學習：
bruise 瘀青
injury 傷害
diffuse 擴散；散布
prickle刺痛；戳；扎
red-eye flight 夜間航班
look sb.in the eye 直視某人
hit the bull's eye 達成目標