Campbell said she had been given a "few dirty pebbles" in the middle of the night.

VOA: standard.2010.08.09

Well, we start out with our usual system, and we have a bunch of little pebbles on it.

还是那个系统，活塞上面放了很多小石子。

麻省理工公开课 - 热力学与动力学课程节选

Well, we start out with our usual system, and we have a bunch of little pebbles on it.

还是那个系统，活塞上面放了很多小石子。

麻省理工公开课 - 热力学与动力学课程节选