The thermos, with the lid on top, It's not a open system your coffee is going to stay warm or hot in the thermos.

顶部盖了盖子的热水瓶，不是开系,你希望你的咖啡在热水瓶里面保持温暖,或滚烫。

麻省理工公开课 - 热力学与动力学课程节选

The system can be an open system, or it can be a closed system, or it can be isolated.

系统可以是开系，可以是闭系，或是孤立系。

麻省理工公开课 - 热力学与动力学课程节选