It's just minus the sum of all these things, because of course these are just defined as the work done by the environment to the system.

等于负的这些东西的和，因为它们的定义是,环境对系统所做的功。

麻省理工公开课 - 热力学与动力学课程节选

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