So, in this class we'll be talking about energy a lot, and it's often useful to draw some sort of energy diagram to visualize the differences in energy that we're discussing.

所以，这堂课我们会讨论很多,关于能量的问题，讨论时，画能级图来使能量差别,形象化常常是很有用的。

麻省理工公开课 - 化学原理课程节选

Now these quantities were useful because you could relate them. The slope of changes, with respect to volume or temperature of the energy with respect to quantities that you understood, that you could measure.

去得到这些量,这些量很有用，而且你们已经知道了，怎么把它们相互联系起来,像这种比例形式的量，能量比上温度或体,或其它你们懂的可以测量量。

麻省理工公开课 - 热力学与动力学课程节选