perforated signal disc

例句：

1. 1.The perforated signal disc was used to indicate the direction of travel.
   穿孔信号盘用于指示行进方向。
2. 2. The perforated signal disc was a crucial component in the navigation system.
   穿孔信号盘是导航系统的关键组成部分。
3. 3. The perforated signal disc helped us navigate through the dense fog.
   穿孔信号盘帮助我们在浓雾中导航。