axle sag

例句：

1. 1. The car's suspension systemis causing the axle to sag.
   汽车的悬挂系统导致轴向下垂。
2. 2. The weight of the load caused theaxle to sag.
   负载的重量导致轴向下垂。
3. 3. The engineer checked theaxle for any signs of sag before installing the new parts.
   工程师在安装新部件之前检查了轴是否有下垂的迹象。