日期:
来源:雅诚德英语网
Regular repeating actions such as sound waves, light waves, or radio waves have a certain frequency, or number of waves per second.
有规律的重复活动如声波、光波、无线电波都有一个特定的频率,或者说是每秒的波动次数。
Regular repeating actions such as sound waves, light waves, or radio waves have a certain frequency, or number of waves per second.
有规律的重复活动如声波、光波、无线电波都有一个特定的频率,或者说是每秒的波动次数。