它们与地球上的河流系统非常相似，地质学家认为它们是早已消失的河流留下的干涸的河床。

They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers.

youdao

尽管一些河流被重新殖民，但原始种群的独特基因已经消失。

Although some rivers have been recolonized, the unique genes of the original populations have been lost.

youdao

这里，外面的世界似乎消失在群山之中，隐没在河流、静水和湿地之中。

Here, the outside world seems to vanish behind enfolding mountains, quarantined away by river, still water, and wetland.

youdao