So, we do this here for the photoelectric effect, and in terms of the photoelectric effect, what we know the important point is that the incoming photon has to be equal or greater in energy then the work function of the metal.

所以，我们做这个是为了说明，光电效应，在光电效应方面，我们知道的最重要的事情,就是入射的光子能量必须等于,或者大于金属的功函数。

麻省理工公开课 - 化学原理课程节选

Because of that, in order to efficient function, then you group all the like activities together.

所以,为了使各种生理功能更加高效化,你就得把各种相似的生命活动分在一起

耶鲁公开课 - 生物医学工程探索课程节选

The basic idea in solving these equations and integrating is you find one answer, so then when you take enough derivatives, the function does what it's supposed to do.

解决这类方程以及积分的基本思想就是,你求出一个解,然后进行多次求导,求导的结果就满足条件

耶鲁公开课 - 基础物理课程节选