She had known Max for some years now, but he was still pretty much an unknown quantity.

她现在认识马克斯也好几年了，但是他仍然是个大大的未知数。

《柯林斯英汉双解大词典》

While it is unknown just how much of this is true, it is certainly known that silk cultivation has existed in China for several millennia.

虽然我们不知道这其中有多少是真实的，但可以肯定的是，丝绸栽培在中国已经存在了几千年。

youdao

The LHC should, though, if all goes according to plan, show up one very well known unknown by creating tiny black holes.

如果一切进展顺利，LHC应制造出一些微型黑洞，以验证这个著名的已知之未知。

youdao

This, many believe, is an insult to India's many well-known and unknown - and unsung - activists who are working quietly and ushering in changes without whining loudly that India has failed itself.

BBC: Can civil society win India's corruption battle?

Spread the marketing funds wide to introduce the public to lesser-known or unknown writers and new writing.

FORBES: The 21st Century Novel: Jaded Ibis Sees a 'Mashup'

It includes objects from more than 100 designers and lenders, including some of the biggest names in the jewelry industry along with well-known independent designers and unknown artisans.

FORBES: Outer Space Jewelry Exhibit Opens to the Public