1·The herders shifted south, following the major river systems into savanna regions.
牧民们向南迁移，沿着主要河流系统进入热带草原地区。
2·These rivers and river systems are known as "exogenous" because their sources lie outside the arid zone.
这些河流和河川系统被称作“外源河流”，因为它们的源头位于干旱地区之外。
3·They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers.
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。
4·Arid lands, surprisingly, contain some of the world's largest river systems, such as the Murray-Darling in Australia, the Rio Grande in North America, the Indus in Asia, and the Nile in Africa.
令人惊讶的是，干旱地区拥有着世界上最大的一些河流系统，如澳大利亚的墨累-达令河、北美的里奥格兰德河、亚洲的印度河和非洲的尼罗河。
5·River systems empty into the sea.
河系最终注入大海。
6·Three river systems, elegant and romantic!
三重水系，典雅浪漫风情！
7·There is the Amazon, parana, and San Francisco three major river systems.
有亚马逊、巴拉那和圣弗朗西斯科三大河系。
8·The river systems of India and Bangladesh are rife with diarrhoeal disease.
印度和孟加拉国的河道系统布满肠道致病菌。
9·But if it did, what would the effect be on the major river systems of southern Asia?
但假如发生的话，它对南亚的主要河流系统将产生什么影响呢？
10·There are rich palaeoseismic vestiges) offsetted ridges and river systems are apparent.
这里古地震遗迹丰富，断错山脊、水系明显。