1. Science is not mysterious. The peak of science can be reached by all warriors who are not afraid of hardships and dare to climb. ——Mao Yisheng

2. Throughout the ages, those who have achieved great things and made a difference to mankind are all the result of down-to-earth and hard work. ——Qian Sanqiang

3. Science is not something that can be gained for nothing. It is true that there is no other way to gain in science except sweating; whether it is enthusiasm, fantasy, or the desire of the whole body and mind, it is all. It cannot replace labor. ——Herzen

4. At the entrance of science, just like at the entrance of hell, this requirement must be made: "All hesitation must be eradicated here; any cowardice will be useless here." ——Marx