In summer, bison roamed freely, 夏季 美洲野牛四处漫步

242. Some grasslands must endure not only fire, but ice.
     一些草原不仅要忍受火的炙烤 还有冰霜
243. As winter approaches,
     冬季来临
244. the prairies of North America begin to freeze.
     北美的草原开始霜冻
245. In summer, bison roamed freely,
     夏季 美洲野牛四处漫步
246. almost continuously cropping the abundant green grass.
     享用着取之不尽的大片青草
247. Now, that grass is not only withered and frozen,
     现在青草不仅枯萎结冰
248. it's about to be buried.
     马上还会被大雪掩埋

来自《行星地球 第二季 第五集 Planet Earth S02E05 草原》第 245 行