UnitedStatesofAmerica, commonly known as the United States, formerly known as Citigroup, is a federal constitutional country located in North America and the oldest constitutional country in the world.

The United States is bordered by the Atlantic Ocean in the east, the Pacific Ocean in the west, Canada in the north and Mexico and the Gulf of Mexico in the south. The capital is Washington, D.C. ..

The United States originated from the North American colony that broke away from British rule in 1776. 13 of the colonial representatives issued the American declaration of independence. After an arduous war of independence, they signed the Paris Convention with Britain in 1783, which has been recognized by all countries in the world since then.

After more than 200 years of development, the territory of the United States has been expanding, and 37 States have joined the Federation. At present, there are 50 states, 1 federal special administrative region and several overseas territories. With a land area of over 9.62 million square kilometers, it is the third largest country in the world. The United States has 300 million residents, the third largest population in the world. The 50 white stars on the American flag represent 50 States; Every time NSW joins the Federation, a star will be added to the national flag on July 4 of the following year. The national flag has seven red and six white stripes and *** 13 stripes to commemorate the original 13 states.

Since People's Republic of China (PRC) was founded more than 200 years ago, the United States has experienced two severe tests: the Civil War (186 1-65) and the economic panic (1930). It still adheres to a liberal and democratic political system and has become a representative country of constitutional democracy and civil liberties. The great economic, cultural, scientific and military influence of the United States runs through the whole 20th century. In World War I and World War II, the United States and its allies won together. After decades of cold war, they finally dragged down the Soviet Union and became the only superpower in the world [5]. Today, the great influence of the United States in the world economy, politics, military and many other fields is unmatched by other countries.