I get to meet a lot of people through the course of teaching, and I recognize a lot of faces.

我认识了很多的人,在教这门课程的过程中，我记得很多张脸。

麻省理工公开课 - 固态化学导论课程节选

Back to this graphic again: unpredictable food supply occurred on the left but doesn't occur on the right.

再回到这张图,对左边的人而言,食物供给难以预计,而右边却并非如此

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选