We use this expression to say that we don't or can't understand something.

我們用這個短語來表示我們不懂或不能理解某事,。

例句1：

Fast food is full of rubbish. Why do people eat it?

I don't know. It's beyond me.

快餐是垃圾食品,，為什么人們要吃它?

我不知道，一直不太理解,。

例句2：

I don't know why they don't practise their English. There's an exam next week.

I know. It's beyond me, too.

我不知道他們?yōu)槭裁床痪毩曈⒄Z,。下周有個考試。

是啊,，我也不明白,。