And they got in this habit of, every time they had a bright, happy text, they'd set this in one kind of mode or key-- a major mode--and every time they had a sad one, they'd set it in minor.

于是人们养成了这样的习惯,每当人们书写欢乐,愉悦的歌词时,他们就设定一个调式或调性,即大调,每当人们书写忧伤的歌词时,他们就定为小调

耶鲁公开课 - 聆听音乐课程节选