We have to invent a process, a chemical extraction process that will make the production of magnesium cheaper so that we will have the opportunity to avail ourselves of energy-efficient materials.

我们必须发明出一种方法，一种化学提炼方法,能够使生产镁变得更便宜,那样我们才有机会,让我们自己用上高效能的材料。

麻省理工公开课 - 固态化学导论课程节选

So it's a very efficient way of securing energy.

因此这是一个高效的保存能量的方法

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

The ones who would seek out calories, the ones who could store and not waste energy, those with an efficient metabolism-- that is those people who took in calories and banked them into their body fat and stored against subsequent famine-- are the ones who would do the best under these circumstances.

那些寻找能量的人,那些储存而不浪费能量的人,那些有着高效代谢系统的人,那些人可以将摄入的热量储存为机体脂肪,以用于对抗即将到来的饥荒,在早先的情况下他们是最适应环境的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选