Mr. Lu Xun's "The Advantages and Disadvantages of Pseudo-Free Books and Electricity": Foreign countries use gunpowder to make bullets to defend against the enemy, but China uses it as firecrackers to worship God; Foreign countries use compass to sail, but China uses it to see Feng Shui; Foreign countries use opium to treat diseases, but China uses it as a meal. It is the same thing, but there are differences in usage between China and foreign countries. The cover is not only electrical.