That's a real fluid boundary between the divine and human realms, if you ask me. But it only happens there, in one spot.

这在神族和人类之间可真是一个不固定的界限，如果你问我的话，然而这种情况只在一个地点发生。

耶鲁公开课 - 旧约导论课程节选

And that was possible in smallpox because of a few characteristics of the disease: one is that it's a--it's purely a human disease, humans are the only organisms that are affected by it.

天花能够被根治的原因在于,这种疾病具有以下几个特点,一是,它是一种只有人类才得的疾病,人类是唯一受天花感染的生物

耶鲁公开课 - 生物医学工程探索课程节选