They just elongated each measure by its same amount so we had harmony changing on each measure, and then in that middle section each chord was changing at the rate of two measures.

但它的基本形式没有改变，而在每个小节中和声都发生了改变，接着在中间的乐节，每个和弦每两小节改变一次。

耶鲁公开课 - 聆听音乐课程节选

So what happened in that middle section?

那在中间一个乐节，音乐有什么变化？

耶鲁公开课 - 聆听音乐课程节选

Like in popular music there's often a couple of verses and a chorus and a bridge and you can predict each different movement of the piece, and that's more regular than-- Couldn't say it better myself.

就像在流行音乐中有很多的曲段，副歌,和过渡乐节，这样你就可以预测到音乐的每一个变化，这样就比别的要规则-,光我一个人不好说太细。

耶鲁公开课 - 聆听音乐课程节选

Let's go on to the next section.

我们再听下一个乐节，I，，VI，，IV，，V，，I，，VI，，IV，，V级。

耶鲁公开课 - 聆听音乐课程节选