So when the Ice Age hit two and a half million years ago, 所以 2500万年前 当冰河时代突然袭来之时
allowed their primate ancestors to survive in the forest of 50 million years ago. 使它们的灵长类祖先 能够在5000万年前的森林中存活下来
just as they were 15 million years ago. 与1500万年前别无二致
Fifteen million years ago, these giant marine cities 1500万年前 这些巨大的海洋城市