The ancients learned nothing, and it takes time to grow old.
What you get on paper is so shallow that you never know what you have to do.
There is also the Southern Song Dynasty educator Zhu's Reading Random Thoughts:
Half an acre of square pond opened, and the sky was overcast.
Why is the water in the pond so clear? Because there is inexhaustible living water for it.
And Zhu's "unexpected success":
It is difficult for young people to learn and grow old, and an inch of time is not light.
Before the sweet spring grass grows in the pond, the plane leaves in front of the steps have rustled in the autumn wind.