apples and oranges不表示蘋果和橘子，那它到底指什么？

apples and oranges是一個常用習(xí)語，表示“兩者天差地別，無法比較;不能混為一談”，它在美式英語中更為常見。

The idiom, comparing apples and oranges, refers to the apparent differences between items which are popularly thought to be incomparable or incommensurable, such as apples and oranges.

例如：

You can't compare them. They are apples and oranges.

你無法比較它們，它們完全不能混為一談。