(2) The construction of the Great Wall in Wan Li embodies the strength of Qin Dynasty and Xiongnu, and the contact between them is actually the exchange and collision of farming and animal husbandry civilizations, which accelerates the national integration; To a certain extent, it intensified class contradictions and led to the demise of the Qin Dynasty, but it was a witness to the wisdom and originality of the ancient working people in China.
(3) The implementation of the county system not only consolidated the central government's local rule and national unity, but also reflected China's transition from a slave society to a feudal society.
(4) "Repairing pool roads and unifying train tracks" is beneficial to the development of transportation, which not only consolidates the central government's rule over local areas and national unity, but also promotes the social and economic development of various regions and the exchanges between ethnic groups, and also reflects the formation of feudal unification.
(5) Taking Xianyang as the capital shows that the political and economic center at that time was still in the middle and lower reaches of the Yellow River.