nitwit n. 糊涂虫

rack one’s brain 绞尽脑汁

work out 解决

really something 很了不起

no guts 没有骨气

say uncle 认输

never say uncle 很嘴硬，永不言败（俚语）

He had racked his brain, but hadn’t been able to work out the answer to the problem.

他已经绞尽脑汁，但是就是找不到问题的答案。

She’s really something.

她真了不起。

You are a nitwit.

你真是个小糊涂虫。

You never say uncle，you wouldn’t admit you are wrong for the life of you.

就你嘴硬，打死不认错。