There's no work being done on, out of the whole thing.

整个过程没有产生功，内部使用的功由这里提供。

麻省理工公开课 - 热力学与动力学课程节选

Arthroscopic surgery in one sense is a fancy example of that, a way of looking inside a joint to see what's happening inside while the person is alive and without hurting them.

关节镜手术就是一个极佳的例子,使用该技术我们可以一窥关节内部,而不影响病人的生命,也不会过分痛苦

耶鲁公开课 - 生物医学工程探索课程节选

As time goes on, we've developed ever more complex machines to study people and we've talked about some of these already: EKG machines, so an example of an electrical device that can be used to monitor a very elaborate function deep inside your body, the beating of your heart and the rhythm of your heart.

如今,我们已经有功能更加复杂的设备,来研究人类,比如之前说到的心电图,我们使用电子装置,对身体内部机能进行精确地监控,具体到心电图就是心跳和心率

耶鲁公开课 - 生物医学工程探索课程节选