But these mammal ancestors 但这些哺乳动物的祖先

117. They emerged into an almost empty world
     它们出现在 一个几乎空无一物的世界中
118. and have been reaping the rewards.
     尽情收割
119. Life is good.
     生命很美好
120. But these mammal ancestors
     但这些哺乳动物的祖先
121. have had little competition or predators,
     几乎没有竞争对手和捕食者
122. until now.
     直到这一刻的到来
123. With the planet recovering,
     随着地球的复苏

来自《我们星球上的生命 第一季 第四集 Life on Our Planet S01E04 冷血动物》第 120 行