A person who " sings the blues" feels sad.

吟唱布鲁斯乐曲的人通常很悲伤。

And feeling good was easy, Lord, when he sang the blues, You know feeling good was good enough for me, Good enough for me and my Bobby McGee.

感觉良好很容易， 上帝，当他唱布鲁斯时，你知道感觉良好对我来说已经足够了， 对我和我的 Bobby McGee 来说已经足够好了。