If you ever hear music rocking back and forth repeatedly between two chords, it's probably tonic,dominant,tonic,dominant.

如果你听到音乐在两个属音里不断前后行进，这可能就是主音，属音，主音，属音。

耶鲁公开课 - 聆听音乐课程节选

So if you hear two chords rocking, it's probably tonic and dominant.

如果你听到有两个和弦，这有可能是主音和属音。

耶鲁公开课 - 聆听音乐课程节选