解释：大部分药材都以新鲜为好，但艾草却以陈年的为佳，体现了药材使用的特殊性。
Pain can be a form of knowledge.
The ability to be alone is the ability to love. It may look paradoxical to you, but it’s not. It is an existential truth: only those who can be alone are capable of love, of sharing, of going into the deepest core of another human being—without possessing the other, without becoming dependent on the other, without reducing the other to a thing, and without becoming addicted to the other.
The selfish gene theory is not a theory about selfishness in the everyday sense. It is a theory about the evolution of behavior.
"We are all completely different people at different points in our lives."