key lever

例句：

1. 1.The key lever is the only thing that can turn the machine on and off.
   这个关键杠杆是控制机器开和关的唯一东西。
2. 2.The engineer used the key lever to adjust the gears.
   工程师使用这个关键杠杆来调整齿轮。
3. 3. The car's key lever was broken, so we had to use a screwdriver to start it.
   汽车的钥匙杠杆坏了，所以我们不得不用螺丝刀来启动它。