英语听力:自然百科 冰冻星球 前往地球尽头—2(在线收听

 I am standing at the North Pole, the very top of the earth. Up here, it's easy to see why the Polar Regions are so cold. The sun never rises high enough in the sky to warm my back. And those rays that do strike the surface are mostly reflected back from this great whiteness. But the fundamental problem is that there is no sun here at all for half the year. 

 
    The polar winter is unrivalled in its harshness and night that lasts for months, only the toughest day, as temperatures plunge/ to minor 70 degrees centigrade. And yet the greatest challenge to life here is not the cold, but the extreme swings between the seasons.
 
    When the sun finally returns, an extraordinary transformation begins. This frozen world begins to melt away. The polar spring brings views of a brief opportunity for life. By summer, the sun no longer sets and works its magic for 24 hours a day. Now, it's a race to breed before the sun departs .By autumn, all but the hardiest abandon/ the poles and the ice extends its grip. Land and sea close/ down for the long polar winter until once again the sun returns. 
 
  原文地址:http://www.tingroom.com/lesson/zrbaike/2011/260350.html