They used a system of measurement called the Body Mass Index to define words like obese and overweight.

VOA: special.2009.07.21

Then, after you define what your system is, whatever is left over of the universe is the surroundings.

当你定义了你的系统后，宇宙的其余部分,就是环境。

麻省理工公开课 - 热力学与动力学课程节选

We're going to find other properties that do care about the history of the system like work, that you put in the system, or heat that you put in the system, or some other variables But you can't use those to define the equilibrium state.

我们还会发现其他一些,与系统的历史有关的性质,比如你对系统做的功，或者你向系统传递的热量，或其他的变量,但你不能用它们,来定义平衡态。

麻省理工公开课 - 热力学与动力学课程节选

There's no heat flowing from the environment to the system. I have to define my terms.

系统与外界间,并没有热传递发生。

麻省理工公开课 - 热力学与动力学课程节选

It depends on what you define, exactly what you define in your system.

它取决于你的定义，尤其是在你系统中的定义。

麻省理工公开课 - 热力学与动力学课程节选