It was a mad idea.

那是个愚蠢透顶的想法。

《牛津词典》

This is not a mad idea.

这个点子并不疯狂。

youdao

I thought it was a really mad idea if it was true.

我当时想，如果这是真的，那想法也真够疯狂的。

youdao

It was a mad idea to climb the mountain in this bad weather.

在这种坏天气去爬山真是愚蠢。

youdao

He had this same mad idea a few years ago.

他几年前就有这种痴心妄想。

youdao

He had this same mad idea a few years ago.

他几年前就有这种痴心妄想。

youdao