The respiratory system plays an important role in maintaining our internal environment at the proper level of oxygen, by bringing the right amount in.

呼吸系统的重要性在于,通过向体内输入适量的氧气,维持人体内环境中的氧平衡

耶鲁公开课 - 生物医学工程探索课程节选

Well, some things that your brain does involve very low-level internal structures.

大脑所参与的部分活动,用到了相当低层的内部结构

耶鲁公开课 - 心理学导论课程节选