Now there's one last triage level that we use in the worst scenarios.

还剩一个分类等级，我们用它来表示最坏的情景。

Ok, let's add the last level of complexity.

好的，让我们添加最后一级复杂性。

Humans can only last a few days without  water before their bodies can't function The exact time frame depends on  the climate, their activity level, their health, and their size.

人类在没有水的情况下只能坚持几天，身体就无法发挥作用。确切的时间范围取决于气候、活动水平、健康状况和体型。