but they don't have their mother's sense of urgency. 不过它们并不像母熊那样着急

59. and the mother has led her cubs a mile from the den.
    母熊已经带领幼熊离巢1英里远
60. It's time to put them to the test.
    现在该是考验它们的时候了
61. They've grown enormously in confidence,
    它们的信心日益膨胀
62. but they don't have their mother's sense of urgency.
    不过它们并不像母熊那样着急
63. At last it seems that they're ready for their journey
    最后 它们似乎做好了旅行的准备
64. and they're only just in time,
    它们刚好赶得及
65. for a few miles from the coast the ice is already splitting.
    离岸几英里远的海面上 冰层已经开始崩裂

来自《行星地球 第一季 第一集 Planet Earth S01E01 从北极到南极》第 62 行