Each seal is indeed swimming for it's life. 每只海豹必须拼命游泳

219. To reach the open sea,
     要到达远海
220. they must cross a narrow strip of water
     它们必须穿越一片狭窄的水域
221. and that is patrolled by great whites.
     大白鲨就在那里逡巡
222. Each seal is indeed swimming for it's life.
     每只海豹必须拼命游泳
223. The shark relies on surprise.
     可大白鲨让人惊奇
224. The great white's turn of speed is powered by a high metabolism.
     大白鲨的速度和力量来自体内高速的新陈代谢
225. They only thrive in cold temperate seas for only these waters contain sufficient food necessary to fuel such a ravenous predator.
     它们只呆在冰冷的海里,也只有大海才有充足的食物 供这种贪婪的掠食者享用

来自《行星地球 第一季 第九集 Planet Earth S01E09 海洋》第 222 行