translation.en: With my classes, I sometimes give them a basic fact that might be revealing with respect to their personality: I tell them that it is virtually impossible for adults to lick the outside of their own elbow.
translation.zh: 在课堂上，我有时 会讲一个基本事实 能揭示人的性格特点： 我说，一个成年人无法 舔到他们的手肘外侧。