I made a stupid mistake.

我犯了个愚蠢的错误。

《柯林斯英汉双解大词典》

How could I have been so stupid?

我怎么会这么傻？

《柯林斯英汉双解大词典》

I'd been tricked and I felt stupid.

我被人骗了，觉得自己真傻。

《牛津词典》

"My dear Fortunato," I said, "I'm afraid I have been very stupid.

VOA: special.2009.02.07

Here's my favorite example of stupid facts I was forced to learn when I was younger--state capitals, right?

下面是我最喜欢的一个关于愚蠢的事实的例子,在我年轻时，我被迫去记忆州首府？

耶鲁公开课 - 死亡课程节选

So we keep track of the types of questions that come up, unless I said something stupid in class or been confusing, certainly.

所以我们对出现的各种各样的问题保持联系，除非我在课程上说了一些愚蠢的,或令人困惑的话。

哈佛公开课 - 计算机科学课程节选

"If it's true, then I'm stupid because I didn't understand anything about this, " Mancini added later.

WSJ: Wigan Grabs Late Winner in FA Cup Upset

While I was alone before my release, pacing back and forth, it was almost impossible not to suspect that I was stupid, that my actions were futile.

CNN: My arrest at Occupy Wall Street

He looked at me as though I was stupid.

BBC: Australia: Where the good life comes at a price