But there was a time 但曾经有一个时期

32. Yet these ancient adversaries are lucky...
    然而它们是幸运的
33. for they can look forward to the end of winter
    因为可以期待冬天的结束
34. and the relief of spring.
    和春天的到来
35. But there was a time
    但曾经有一个时期
36. when winter never seemed to end.
    冬天似乎永远不会结束
37. Two and a half million years ago,
    250万年前
38. changes in the Earth's orbit, ocean currents, and carbon dioxide levels
    地球轨道、洋流 和二氧化碳水平的变化

来自《我们星球上的生命 第一季 第八集 Life on Our Planet S01E08 冰与火的世纪》第 35 行