stepped pulley

例句：

1. 1. The engineer designed a stepped pulley system to increase the efficiency of the machine.
   工程师设计了一个梯级滑轮系统来提高机器的效率。
2. 2. The construction worker used a stepped pulley to lift heavy materials without straining his back.
   建筑工人使用一个梯级滑轮来举起重物，而不会感到背部疲劳。
3. 3. During the construction phase, the team used stepped pulleys to move heavy equipment around the site.
   在施工阶段，团队使用梯级滑轮来移动重型设备。