Depending on what you call external and internal environment, this path that I'm tracing here, deep within your digestive system, is really directly connected to the outside world through both ends.

基于你们所谓的外环境和内环境,我在这里我所指的消化系统内部通路,它的两端确实与外界环境直接相通

耶鲁公开课 - 生物医学工程探索课程节选

Then you put two pistons, one on that side here and one on this side here, and the external pressure here, we're going to call that p1.

接下来我们放进两个活塞,一个在这，一个在这,这变外界的压强为p1；

麻省理工公开课 - 热力学与动力学课程节选