Rainfall is not completely absent in desert areas, but it is highly variable.
沙漠地区并非完全没有降雨，但它的变化很大。
2
The impact of rainfall upon the surface water and groundwater resources of the desert is greatly influenced by landforms.
降雨对于沙漠地表水和地下水资源的影响很大程度上取决于地形。
3
The areas that are now desert were, like all arid regions, very susceptible to cycles of higher and lower levels of rainfall, resulting in major, sudden changes in distributions of plants and animals.