? major changes in political structures, social and economic life, occurred during :The Sui dynasty

Sui Dynasty only had three emperors (last one only be emperor for one year) but it was regarded by the historian as an important and great dynasty. It fulfilled the unification of all the nation , including the minorities groupes, for the first time after the Han Dynasty. It provided a good fundation for the later Tang Dynasty. In political struction, Sui invented the central government system of Three Councils and Six admissions. Successive dynasties followed or make minor changes. Tang was an open society and there are many people from other countries in the capital city, present Xi'an. Anyway, you can check out https://www.travelchinaguide.com/intro/history/ for more facts.