We know it has to big anyway, since we can extract heat from it without changing the temperature.

我们知道它必须很大，因为我们得从中提取热量,但不改变它的温度。

麻省理工公开课 - 热力学与动力学课程节选

He thinks about examples, he surveys examples and tries to extract a kind of metaphysical principle from this.

他思考一些例子，调查研究它们,试图从中提取一种,哲学原理。

耶鲁公开课 - 死亡课程节选