英语听力:自然百科 北极熊 冰上间谍 Spy_Bear—19(在线收听

 Finally she leaves him some scraps to chew on. A young male arrives, a dangerous situation for the cub. She growls a warning. It’s not enough. The cub slips. The mother must get her cub away from danger as quickly as possible.

They head north. She knows that this is where the ice, and with it the seals will first return.
It’s now September, but the sea might not freeze again for another two months. Her cub is unlikely to survive that long.
But there is hope on the horizon. An ice-rainbow heralds change. In the far north, temperatures drop at last. And ice sheets start to grow rather than disappear.
Then a miracle happens, building pressure combines with powerful southerly currents to push the drift-ice southwards.
 
  原文地址:http://www.tingroom.com/lesson/zrbaike/2010/259548.html