So the pieces we need are not only an image of Ruth, even if an imperfect image of Ruth, we also need some prior acquaintance with Ruth.

所以我们不只需要露丝的照片,甚至不能是一张不像露丝的照片,我们必须之前就熟知她才行

耶鲁公开课 - 死亡课程节选

If you have imperfect competition, it's somewhere between perfect competition and no competition.

如果你们想得到不完全竞争的局面,它就在完全竞争和垄断之间

耶鲁公开课 - 博弈论课程节选