Most of our popular music, folk songs and things like that, are written in duple meter and in a major key.

大多数的流行音乐,民歌,以及类似的音乐,是写在二拍子和大调上面

耶鲁公开课 - 聆听音乐课程节选

Occasionally, you get things written in triple meter and in a minor key--minor key.

偶尔,有一些是由三拍子,和小调组成

耶鲁公开课 - 聆听音乐课程节选