know-nothing

I know nothing at all about the recent happenings there.

对那里近来发生的事我点儿也不知道。

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

对那些对它无所知的人来说可能显得很难理解。

He knows nothing of unprofessional matters.

与专业无关的事, 他什么也不知道。

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

我忙不迭地补充说，我当时对那个骗局无所知。

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

但是，过程中，我们对自然界的“numina”（内现实）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的问题实际上无所知时, 就不再开口了。

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

我只知道维基是个非常好用的，免费的，不断成长的百科全书。