The adventures of Xiao Na and Da Cao on the road to learning chemistry
The same is true for "difficulty". Facing cliffs, you can't see a crack in a hundred years, but with an axe, you can advance inch by inch, and you have to advance foot by foot. Keep accumulating, leaps and bounds will come, and breakthroughs will follow. - Hua Luogeng
Purpose: Without extra diligence, there will be neither talent nor genius!