"Google hopes to benefit from it by improving our search and we expect that we will make some money as we sell the books, but the motivation is not the money we're going to make from selling books,"

VOA: standard.2009.12.31

What we use as our motivation here.

我们用什么作为动力呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

And the motivation for choosing a pair like that is easy to see, if we look at our condition for spontaneous change or general condition.

我们这样选择的动机,很明显，如果考察我们所考虑的自发变化的条件,或者更一般的条件。

麻省理工公开课 - 热力学与动力学课程节选