1, other meanings: tapping hard will make a loud sound, and tapping lightly will make a small sound.

2, from: "Book of Rites" cloud: Be kind to the questioner, such as ringing the bell, the small one is small, and the big one is loud.

3. Interpretation: A teacher who is good at answering questions is like ringing a bell. If you tap, the bell will be smaller; A heavy knock on the door will ring.

4. Expansion: The process of waiting for questions is actually a process of listening. Teachers should grasp the correct questions and understand the meaning of the questions by listening. To achieve the realm of "goodness", teachers must practice "listening skills" to be able to hear, hear clearly and understand.