听力文本

With each passing day, the sun climbs higher in the sky
随着时间一天天过去，天上的太阳升得越来越高
and its rays strike the Arctic more directly.
阳光逐渐直射到北极来。
It's spring and new life stirs.
新的生命在春天的气息中开始蠢蠢欲动。
The polar bear cubs emerge from the den in which they were born.
小北极熊从洞穴中探出头来。
Their mother stretches her legs after five months under the snow.
它们的母亲在雪下呆了5个月后终于可以出来伸伸腿。
They are just two months old and instinctively follow her lead.
小熊才两个月大，本能地跟在母亲后面。

A steep slope makes the best site for a den, but it's a tricky place to take your first steps.
陡峭的斜坡是穴居的好地点，但第一次踏出脚时是不能掉以轻心的。
It may look like fun but this is serious training for the task ahead.
可能看起来很好玩，但这都是为马上来临的严峻挑战所做的训练。
There is no food on the slopes
山坡上面没有食物，
and the family will need to head out across the frozen sea before the mother's milk runs dry.
在母熊奶水干涸之前，一家人需要穿越冰封的海洋。
Two weeks later, they are ready.
两周后它们做好了准备。
Out on the sea ice, the female can hunt for seals
雌熊有可能在海冰上捕食到海豹，
but it will take all her mothering skills to keep her cubs safe in this dangerous world of ice.
但是这个冰雪世界危机四伏，要保护好自己的幼仔，母熊必须施展出所有的本领。

视频及简介

地球的南北极分别是南极洲和北冰洋，它们几乎长年都是冰天雪地。春去秋来，太阳直射点发生迁移的时候，这两个冰封的世界随之发生最极端的季节变化，从极地冬天的黑暗和严寒转变到极地夏天的午夜和光明，太阳全天24小时不落。