This type of famous sayings are as follows:

1. "The most important thing in learning is doubt. A small doubt leads to small progress, and a big doubt leads to great progress."

2. "Doubt is the beginning of thinking and the end of learning."

3. "The biggest mistake in life is to constantly worry about making mistakes."

4. "The value of a person is determined at the moment of temptation."

5. "Raising a problem is often more important than solving a problem."