这就是他为什么追根求源，重新发现了中国民族音乐之美。

This is why he went back to his roots and rediscovered the beauty in Chinese folk music.

相信口红指数理念的人追根求源，发现大萧条时期出现了这个现象，尽管当时经济骤降温，化妆品的销售却增长了25%。

Believers in the theory trace the phenomenon back to the Depression, when cosmetic sales increased by 25%, despite the convulsing economy.