The modern history of China began with the outbreak of the Opium War between China and Britain in 1840 and ended with the founding of People's Republic of China (PRC) in 1949. The modern history of China has been established since People's Republic of China (PRC) (PRC) 1949. In other words, what was the United States doing from 1840 to 2008? First of all, the westward expansion of the United States (1820- 1849) came to an end, and thousands of people moved to the border of the United States, and even went deep into the territory of Mexico and Oregon between Alaska and California. Then the North-South conflict (1850- 1869) broke out, which was actually the opposition between the northern bourgeoisie and the southern plantation slave owners. 18665438+April 0 to 65438+April 0865, the civil war was called the civil war, and Lincoln became famous in one fell swoop. Finally, the union army won. The United States was unified, followed by industrialization and reform (1870- 1929), which was the second industrial revolution. The United States and Germany are both lucky in this revolution, ranking first and second respectively. In 2007, they also participated in the outbreak of 19 14. 1939 World War broke out, 1940 Japan attacked Pearl Harbor, and the United States entered the war. 1945 ended. Pursuing hegemonism after the war. At one time, relations with the Soviet Union were tense, and the Cold War broke out until the disintegration of the Soviet Union. Entering the third scientific and technological revolution in the mid-1970s, the economy once served the Soviet Union and then expanded in the late 1970s. Directly or indirectly participated in the Vietnam War and the Middle East War since the war. After the 200 1, 9 1 1 incident, he joined the anti-terrorism action.