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

2. Raising questions is more important than solving them. ——Einstein

3. 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

4. Problems are midwives, they can help the birth of new ideas. ——Socrates

5. Scholars must first doubt. ——Cheng Yi

6. Question, rather than question, "A real singer can sing out the silence in people's hearts." ——Chai Jing

7. Doubt is the beginning of thinking and the end of learning. ——Confucius

8. Those who do not doubt when there is doubt have never learned; learning requires doubt. ——Zhang Zai

9. 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

10. Questioning is the first step towards philosophy. —— Diderot

11. You cannot see the truth without doubt. ——Li Siguang

12. People who don’t ask will always be together with ignorance. ——East Africa

13. Questioning customs from all aspects is an inevitable stage of development for every person with a high level of thinking. ——Emerson

14. The key to all science is undoubtedly the question mark. ——Balzac

15. Those who have no doubts in reading must learn to have doubts, and those who have doubts must have no doubts. This is the only way to make progress. ——Zhu Xi

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

17. A person who is eager to ask questions is only five kinds of fools; a person who is ashamed to ask questions will be a fool for life. ——Anonymous

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

19. A person who is good at asking questions is like attacking a strong tree. He will first make it easy, 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"

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

21. Teachers use doubts, and friends use doubts.

——Li Xing