signals

She adjusted the antenna to improve the signals on the television.

她调整天线，以改善电视信号。

The dark clouds in the sky are signals that a storm is approaching.

天空中的乌云是暴风雨即将来临的信号。

I could see the signals from the train tracks changing from red to green, indicating it was safe to cross.

我能看到火车轨道上的信号灯由红色变成绿色，表明可以安全地过马路了。