And what we find, the first example of a Bronze Age-- and I use the word civilization now for the first time, because before the Bronze Age-- there is nothing that we would define as civilization.

我们发现的第一个文明出现在青铜时代,也是我第一次用文明这个词,因为在青铜时代之前,没有任何东西能称之为文明

耶鲁公开课 - 古希腊历史简介课程节选

c We know it's very specific for light because in this equation is c, the speed of light. So any time you go to use this equation, if you're trying to use it for an electron, just ask yourself first, does an electron travel at the speed of light?

我们知道它只对光适用是因为在这个方程里有,光速，所以下次你们用这个方程前，如果你们要把它用到一个电子上，先问问你自己，电子的运动速度是光速吗？

麻省理工公开课 - 化学原理课程节选