And the reason is, and this will come up on the problems and a lot of students end up using this equation, which is why I want to head it off and mention it ahead of time, we can't use an equation because this equation is very specific for light.

原因是，很多同学在解题时,都会用这个方程，所以我要,事先提醒你们一下,我们不能用这个方程，因为它只对光是用。

麻省理工公开课 - 化学原理课程节选

But it's variable because it doesn't always go off on the thousandth time.

但中奖比率是变化的,因为你并不总在拉杆一千次的时候中大奖。

耶鲁公开课 - 心理学导论课程节选