Many years! The United States has hundreds of years of history and knowledge, 1 American War of Independence; 2. Civil war; 3, the history of blood and tears in the west (civilization point is that the western region has been developed, a bit like China's, to be exact, others are in front, we learn from others); 4. Industrial Revolution; Then there are modern times, two world wars, and the transformation of global hegemony between the United States and Britain; Almost. Have you learned anything about the senior high school entrance examination?