countershaft unit

例句：

1. 1.The machine's countershaft unit is responsible for transmitting power to the wheels.
   机器的中速轴单元负责将动力传输到车轮。
2. 2. The engineer carefully inspected the countershaft unit before installing it in the engine.
   工程师在安装发动机前仔细检查了中速轴单元。
3. 3. The countershaft unit was designed to improve efficiency and reduce noise during operation.
   中速轴单元的设计旨在提高操作效率并减少噪音。