What does Master Han Yu mean by idioms?

Preach and teach

Cai Mao

way

Xiaoyou

used at the end of a sentence

Explain and teach, teach.

The source of Tang Hanyu's Teacher's Theory: "Ancient scholars must have teachers. Teachers, so preach, teach and solve doubts. "

Structural joint idioms

Used as predicate and object; Used of teachers, etc

Solving problems in synonym teaching