know-nothing

I know nothing at all about the recent happenings there.

对那里近来发生事儿也不知道。

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

这对那些对它无所知人来说可能显得很难理解。

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.

忙不迭地补充说，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，在这过程中，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.

只知道维基是个非常好用，免费，不断成长百科全书。