纪录片《我们的地球》 第04期 从南极到北极（4）（在线收听）

The sea ice still holds firm, but it won't last much longer.

海面上的冰层依然坚固，但是这种情况不会持续太久

Day 10, and the mother has led her cubs a mile from the den.

第10天，母熊已经带领幼熊离巢1英里远

It's time to put them to the test.

现在该是考验它们的时候了

They've grown enormously in confidence, but they don't have their mother's sense of urgency.

它们的信心日益膨胀，不过它们并不像母熊那样着急

At last it seems that they're ready for their journey and they're only just in time,

最后，它们似乎做好了旅行的准备，它们刚好赶得及

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

Now the mother can start hunting for the seals they must have,

现在母熊将猎杀海豹，获取紧需的食物

but she's leading her cubs into a dangerous new world.

而它也正带着熊崽们进入一个危险的新世界

Nearly half of all cubs die in their first year out on the ice.

大约有近一半的幼熊会在第一年的冰上历险中丧生

Summer brings 24 hours of sunlight and the thawing shifting landscape.

夏季意味着全天24小时的日照，融化的冰雪不断改变着地貌

Further south the winter snows have almost cleared from the Arctic tundra.

在更远的北极苔原上，冬雪几乎已经完全消失