1840 The Opium War was the beginning of modern history. From 1840 to 1949, it was divided into two periods:1840-19 was the old democratic revolution period, and19 was the old democratic revolution period. It is a period of modern times, in which 1949- 1956 is to realize the transition to socialism, that is, the three major transformations, and then it takes about ten years for socialism to meander forward in exploration, 1966- 1976 is the Cultural Revolution, and 1978 is the society.