The people in her photographs show themselves, but a great deal about them remains hidden as well.

VOA: special.2009.08.09

And, just to show some of the hidden balance here, 1 here we have one mole. I don't put a one in front.

这儿有一些隐藏的平衡，比如说这个1摩尔，我并没有在前面写了一个。

麻省理工公开课 - 固态化学导论课程节选