但是，暗能量却是一个未知的未知。

Dark energy, however, is an unknown unknown.

youdao

主观上的不确定即“未知的未知”。

Subjective uncertainty is about the “unknown unknowns”.

youdao

主观的不确定性则关于“未知的未知方面”。

Subjective uncertainty is about the "unknown unknowns".

youdao

that spiritual sense that the divine is always shrouded around by some Cloud of Unknowing.

那种精神的感觉,那种神圣感一直被某种，未知的云彩所缭绕。

耶鲁公开课 - 1945年后的美国小说课程节选

I want to show you how easy it is to change the code. But, notice, once I've added this I actually have a problem. This is now an under-constrained problem. I have more unknowns than I have equations.

我加上这个条件后,我马上面临一个问题了,这就是现在是一个非约束性问题了,我的未知数比方程数多,你从代数中可以知道。

麻省理工公开课 - 计算机科学及编程导论课程节选

This made me think of Mississippi Gene too and as the river poured down from mid America by starlight I knew, I knew like mad, that everything I had ever known and would ever know was One.

这又使我想起密西西比的吉恩,以及河流从美国中部倾斜而下的景象，我知道是很疯狂地，很疯狂地同样也有，我发现所有我知道或未知的事都是一体。

耶鲁公开课 - 1945年后的美国小说课程节选