"This is data under primary energy sources of all the countries.

VOA: standard.2010.08.03

If I want to take the average energy of all of those, what I can do is go over to my data set.

如果我想得到这所有电子能的平均值，我就得去看一下我的数据库。

麻省理工公开课 - 固态化学导论课程节选