In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

A ravine usually has steep sides , and they are 20-70 % in gradient .
A ravine is generally a fluvial slope landform of relatively steep ( cross-sectional ) sides , on the order of twenty to seventy percent in gradient .