Answer 1. Taking advantage of being close to the border, Shanxi businessmen lost their border salary and gained rich profits; The development of commodity economy provides conditions for the development of Shanxi merchants. The change of folk customs is: from attaching importance to agriculture to advocating commerce, from advocating simplicity to extravagance. ③ Reason: Shanxi merchants used funds to buy houses on the land, which affected the further development of their business. Farmers are poor and have low purchasing power, which is not conducive to the further development of business; The decadent feudal system is the fundamental reason that hinders the development of Shanxi merchants. (4) The great powers used trading ports to dump goods and export capital to China, and brought China into the world capitalist market; It accelerated the disintegration of natural economy, promoted the development of commodity economy and stimulated the emergence of Chinese national capitalism. It is the deepening of semi-feudal and semi-colonialism in China.