and the cubs must have the shelter of the den. 熊崽们必须回到洞中避寒

45. That is where she hunts for the seal she needs to feed her cubs.
    而母熊则需要在那里捕杀海豹 喂养幼熊
46. And she must get there before the ice breaks up.
    因此它必须在冰层破碎之前到达那里
47. For now though it's still minus thirty degrees
    而现在的气温仍然有-30℃
48. and the cubs must have the shelter of the den.
    熊崽们必须回到洞中避寒
49. It's six days since the bears emerged
    现在是北极熊现身后的第6天
50. and spring is advancing rapidly.
    春色匆匆
51. But even now blizzards can strike without warning.
    但即使是现在 暴风雪 仍会在毫无征兆的情况下来袭

来自《行星地球 第一季 第一集 Planet Earth S01E01 从北极到南极》第 48 行