These two relations involving entropy are also useful because they'll let us see how entropy depends on volume and pressure.

这两个涉及熵的关系也非常有用,因为他们告诉我们,熵和体积，压强的关系。

麻省理工公开课 - 热力学与动力学课程节选

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

If I'm working under conditions of constant temperature and volume, that's very useful.

如果在恒定的温度和体积下,进行一个过程，这是非常方便的。

麻省理工公开课 - 热力学与动力学课程节选