And the idea is you fast forward and good students start failing algebra all of the sudden, and start failing calculus all of the sudden, despite being smart, despite having good teachers, and it's usually because they have these Swiss cheese gaps that kept building throughout their foundation.
如果你回忆一下， 好学生开始突然就在代数上跌倒， 开始栽在在微积分上， 尽管还是同样的聪明，同样的有老师在指导。 之所以出现这样的情况是因为他们在有 瑞士干奶酪沟这样的地基上建筑。