例句與造句

1. Indeed, even in most arid zones, there tends to be few problems with variability of runoff because most usable sources of water come from high mountain regions which provide highly reliable glacier melt as the chief source of water, which also comes in the summer peak period of high demand for water.
2. It's difficult to find variability of runoff in a sentence. 用variability of runoff造句挺難的