once in a blue moon 百年一遇（很少發生）
He passes his exams once in a blue moon!
他很少通過他的考試！
I cook once in a blue moon!
我很少做飯！

This movie always makes me blue!
這個電影總是讓我感到悲傷！

That blue language is not welcomed here！
在這里，我們不歡迎大家說臟話！

I am kinda blue, can you help me take me home!
我有點兒喝醉了，可以來接我回家嗎！

Black and blue 青一塊紫一塊

She is feeling surprised after hearing that news out of the blue!
她突然間聽到這個消息，十分的驚訝！

She has some true-blue friends, I am jealous!
她有一些真朋友，我好嫉妒啊！

This is like choosing from between the devil and the deep blue sea!
這個選擇讓我進退兩難！