And you see where the most electronegative elements are, and fluorine is the most electronegative of the active elements.

你找一下电子力最大的元素在哪，氟是活泼元素中,电子力最大的。

麻省理工公开课 - 固态化学导论课程节选

Then, I bring the elephant and I pull the spring by the same amount and I find the acceleration of the elephant and the denominator is obviously the mass of the elephant.

然后我再找来大象,用相同的力去拉弹簧,大象就具有了加速度,很明显,分母就是大象的质量

耶鲁公开课 - 基础物理课程节选