Books are really rich, but nothing is immortal.
Poems and books have been handed down from generation to generation for a long time.
Second, learning without thinking is useless, and thinking without learning is lazy.
When you use books, you don't hate them so much. You can learn by paying attention everywhere.
Third, sit like a clock.
Fourth, there is no law, there is no fixed law, this is the ultimate law!
I wonder if there is?