1. The ears have no bottom and can be heard from morning to night. ——Africa

2. Scholars must first be suspicious. ——Cheng Yi

3. Deep in the human soul, there is a deep-rooted need, which is to hope that oneself can be a discoverer, researcher, and explorer. In the spiritual world of children, this need is particularly strong. ——Suhomlinsky

4. Scholars must first doubt. ——Cheng Yi

5. The spirit of skepticism is an important part of the scientific spirit. ——Zhou Guangzhao

6. Thinking starts with questions and surprises. ——Aristotle

7. He who does not doubt when he is doubtful has never learned; learning requires doubt. ——Zhang Zai

8. A person who is good at asking questions is like attacking a strong tree. He will first change it, and then he will understand it. After a long time, he will explain it to each other. Those who are not good at asking will do the opposite. () - "Xue Ji"

9. A person who is good at doubting does not doubt what others doubt, but doubts what others do not doubt. ——Fang Yizhi

10. If your ears have no bottom, you can hear from morning to night. ——Africa

11. Thinking starts with questions and surprises. ——Aristotle

12. A suspicious person does not doubt what others suspect, but doubts what others do not doubt. ——Fang Yizhi

13. You cannot see the truth without doubting. ——Li Siguang

14. There is no doubt that there are doubts in learning, and doubts lead to progress; small doubts lead to small progress; big doubts lead to great progress. ——Lu Jiuyuan Song