引索

例句：

1. 1. The engineer used a lead to guide the car through the tunnel.
   工程师用一根铅垂线来引导汽车穿过隧道。
2. 2.The rope was used as a lead to stop the horses from running away.
   绳子被用作引导绳，以防止马匹逃跑。
3. 3.The scientist attached a lead to the end of the wire to make it easier to control.
   科学家将一个铅垂线连接到电线的末端，以便更容易控制。