signal light engine telegraph

例句：

1. 1.The policeman used his flashlight tosignal the driver to stop.
   警察用他的手电筒向司机示意停车。
2. 2. Thetraffic light is a common signal for pedestrians crossing the street.
   交通灯是行人过马路的常见信号。
3. 3. Thepilot used a signal toguide the plane safely into therunway.
   飞行员使用信号引导飞机安全地进入跑道。