rolling section of hump

例句：

1. 1.The rolling section of the machine is where the parts are assembled.
   机器的滚动部分是组装零件的地方。
2. 2. The rolling section of the road was damaged during the storm.
   暴风雨期间，道路的滚动部分受损了。
3. 3.The rolling section of the car has a smooth surface for easy driving.
   汽车的滚动部分有一个光滑的表面，便于驾驶。