Our immune system's function is to keep us healthy in the face of an environment where there are lots of things that could potentially harm us.

我们免疫系统的功能就是保持自身健康,在面对危机四伏的环境时,使我们免受伤害

耶鲁公开课 - 生物医学工程探索课程节选

It's folly to think that we have about us protective spirits who might actually keep us from harm.

认为真的有神灵在周围,庇佑我们不受伤害是愚蠢的。

耶鲁公开课 - 弥尔顿课程节选