For 3.8 billion years, 38亿年来

187. This may look like the surface of an alien planet...
     这里的地表看上去仿佛如同外星世界
188. ..but these strange patterns are channels of freshwater...
     但这些奇异的图案实际上是通往海洋的
189. ..flowing towards the sea.
     一条条淡水河道
190. For 3.8 billion years,
     38亿年来
191. ever since the first rains fell...
     自从第一滴雨水洒落大地
192. ..freshwater has been making this journey.
     淡水便无休止的循环往复
193. But today, two thirds of our world's great rivers
     然而今天 世界上三分之二的大江大河

来自《行星地球 第三季 第四集 Planet Earth S03E04 淡水》第 190 行