Ask the canal to be so clear, because there is running water at the source. Zhu stressed the need to constantly supplement new knowledge.
A threesome requires a teacher. Confucius emphasized that modesty is attitude and the cornerstone of progress.
Teenagers only know how to play, but don't know how to study hard. When they are old, they regret why they didn't know how to study hard when they were young. Pointed out that we should seize the youth to learn.
Teacher, preach and teach. Han Yu's Teacher's Theory points out that teachers should not only talk about knowledge, but also teach students the truth of being a man and doing things.