Yale University is a non-profit corporation; the price of a share in Yale University is undefined-- it's zero over zero.

耶鲁大学可以看作是个非盈利组织,它的股价无法定义,是零除以零

耶鲁公开课 - 金融市场课程节选

A progenitor cell, the definition, it just means it can generate the cells that are typical of that tissue or that organ, so it's capable of becoming these mature classes of cells.

祖细胞的定义就是,它能产生那个器官或者组织内的,所有的典型细胞,所以它可以成为那一类的成熟细胞

耶鲁公开课 - 生物医学工程探索课程节选