I believe that the United States had no imperialistic motives for entering WWII. Because Great Britain, Russia, and Germany all used to be empires at some point in their history, and they might have wanted to become empires again, whereas America had no such wishes.
1840 is when papers required stamps.
Sun Yat-sen was the leading figure in the national struggle of the people of China. The popular democratic revolution of 1911 was led by him and his party, Tung Meng-hui. This revolution led to the overthrow of Manchu rule in China (The Quing dynasty was the last imperial dynasty in China and ruled from 1636 until the overthrow in 1912) and the establishment of the Republican form of government.
Hope this helped a little. Also if you have any questions then you feel free to ask!! Best of luck as always.
