...if there's one thing we've learned from the past... 历史告诉我们
Freed from the constant battle to find food, 由于不用再为寻找食物而不断争斗
We freed ourselves from the uncertainty of a hunter-gatherer existence 我们通过与大自然结盟
had set us apart from other primates 使我们与其他灵长类动物区分开来
Before long, the walls started to crumble from the inside out... 不久之后 墙开始从内部碎裂
the pressure from behind increased. 来自后方的压力增加
The only thing stopping the water from flooding the land to the west 阻止水流向西淹没陆地的
The descent from the treetops to a life on the forest floor. 从树上下到森林地面生活
The teenager will never stray from the herd again. 这只小象再也不会离队