young people learn easily, but old age is difficult, and an inch of time cannot be wasted. -Zhu Xi
Black hair doesn't know how to study hard early, but white hair regrets how to study late-Yan Zhenqing
There is a path of diligence in Shushan, and there is no limit to learning the sea-Han Yu
He is diligent in his career, but he is barren in playfulness; What is done is thought, but it is destroyed. -Han Yu