...and was about to change our planet forever. 而且即将永远改变我们的星球
But this is the story of what was happening beneath the waves. 但本集将讲述的是海浪下发生的故事
much of our world was fiercely inhospitable... 我们世界的许多地方 都极不适宜生存
It was the world's fifth mass extinction. 这是世界上第五次大规模灭绝
when Earth was stable for 100 million years. 地球保持了一亿年稳定状态
was one reason terror birds went extinct. 是骇鸟灭绝的原因之一