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 will be doubts in learning. If there is doubt, there will be progress. If there is little doubt, there will be small progress. If there is great doubt, there will be 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