an unbroken line of ancestry stretching back four billion years 一条绵延40亿年的连续谱系
It's actually two thousand separate reefs that together form a barrier stretching for over a thousand miles along Australia's northeastern coast. 大堡礁由超过2000个独立的珊瑚礁组成 绵延在澳大利亚东北部海岸,长度超过1000公里