** 美劇筆記 ***
be like chalk and cheese
天壤之別，大相竟庭，chalk 粉筆, cheese乳酪,一個用來畫線寫字，一個可食用

If two people are like chalk and cheese, they are completely different from each other:

My brother and I are like chalk and cheese.

我哥哥跟我個性完全不一樣。
(圖片出自Above Suspicion 2)