你怎么会这么愚蠢？

How could you be so ___stupid?

是谁想出晚上旅行的蠢主意？

Whose ___stupid idea was it to travel at night?

我觉得那很蠢，因为在足球中你不能像兰博一样。

I think that's ___stupid, because in football you can't be like Rambo.