What the whole note is, what all these symbols are are simply representations of duration so we have a symbolic language here that's going to represent the horizontal axis the axis of duration.

什么是全音符,这些符号又都是什么呢,这些就是简单代表了持续时间,因此我们这里有一套符号语言,来代表横轴,就是时值的那条轴

耶鲁公开课 - 聆听音乐课程节选