notched semaphore blode

例句：

1. 1. The notched semaphore blode is used to indicate the presence of a vehicle on the road.
   刻槽信号灯用于指示道路上车辆的存在。
2. 2.The notched semaphore blode was installed at the entrance of the school to alert pedestrians.
   在校园入口处安装了刻槽信号灯以提醒行人。
3. 3.The notched semaphore blode has been replaced by LED lights in many cities to reduce traffic congestion.
   许多城市已经用LED灯替换了刻槽信号灯，以减少交通拥堵。