Ancient times:1before the middle of the 9th century (1840 is the dividing line between ancient and modern China, with the Opium War as the dividing line, marking China's entry into a semi-colonial and semi-feudal society).

Modern times: 1840- 19 19 (Taking the May 4th Movement as the dividing line, China changed from an old democratic revolution to a new democratic revolution. )

Modern: 19 19- 1949 (with the establishment of new China as the dividing line).

Contemporary: 1949- Today