| 1. | The sahara ' s topographical features include shallow basins , large oasis depressions , serirs or regs ( gravel - covered plains ) , plateaus , mountains , sand sheets , dunes and sand seas ( ergs ) 撒哈拉沙漠地形特点包括:浅的盆地、大的萧条的绿洲、砂砾性沙漠或砾质沙漠(碎石覆盖的平原) 、高原、沙席(小沙原) ,沙丘和沙海(砂质沙漠) 。 |