know-nothing

I know nothing at all about the recent happenings there.

对那里近发生事我一点儿也不知道。

This might seem very perplexing to those who know nothing about it.

这对那些对它一无所知可能显得很难理解。

He knows nothing of unprofessional matters.

与专业无关事, 他什么也不知道。

I hasten to add that I knew nothing of the fraud at the time.

我忙不迭地补充，我当时对那个骗局一无所知。

However, we can know nothing through this process about the "numina" (inward realities) of nature.

但是，在这一过程中，我们对自然界“numina”（内在现实）依然毫无所知。

He closed up when he found he knew practically nothing about the subject under discussion.

当他发现自己对所讨论问题实际上一无所知时, 就不再开口了。

I know nothing but Wikipedia is a cyclopedia which is easy to use,free and grow continuously.

我只知道维基是一个非常好用，免费，不断成长百科全书。