The United States of America, referred to as the United States for short, is a federal republic and a constitutional state composed of Washington, D.C., 50 states [1], Guam and many other overseas territories. The United States originated from the North American colony that broke away from British rule in 1776. /kloc-the colonial representatives of 0/3 states jointly issued the American Declaration of Independence, and 1783 signed the Paris Convention with Britain, which was recognized by all countries in the world.

The main part of the United States is located in the middle of North America. In the original version of the CIA World Survey, the total area of the United States was 9,372,665,438+0989 to 1996. 1997 was revised to 9.63 million square kilometers (plus the Great Lakes and coastal waters such as estuaries, harbors and inland seas under the sovereignty of the United States), with a population of 320 million. It is an immigrant country and speaks English commonly [2].