复滑车

例句：

1. 1. The engineer designed a complex system to control the machine.
   工程师设计了一个复杂的系统来控制机器。
2. 2. The multi-level slide is perfect for teaching children about gravity.
   多层次滑梯非常适合教孩子们关于重力的知识。
3. 3. The safety features of this new model are impressive, including a retractable slide.
   这款新型模型的安全特性令人印象深刻，包括一个可伸缩的滑梯。