An antenna is used for radio, television, radar and so on. 天线用于广播、电视、雷达等等。

　　It works in air and under the water. 它适用于空中和水下。

　　Antennas send signals and receive signals. 天线发送和接收信号。

　　Antennas make those signals stronger, so people can listen to the radio better and watch TV more clearly. 天线使那些信号变得更强，因此人们能更好地听广播、更清晰地看电视。

　　Thomas Edison and Heinrich Hertz used antennas and developed them very well in the 1800s. 十九世纪，托马斯·爱迪生和海因里希·赫兹使用天线并很好地发展了它们。