The United States, among the other nations on the two American continents as well as France and Switzerland in Europe, is a Republic, which means we have a republican form of government under which the head of state is not a monarch.
（范围）
In a Republic, people govern themselves by appointing a government which serves people’s interests. By contrast, the tsar - ruler of Russia, a pure monarchy - dictates its people what to do by making laws that people have no say about, and can even start a war as he pleases.
What's more, most monarchies also have a privileged class - the aristocracy that can pass on their rank and parliamentary positions to their heirs by blood. In a republic, however, people are free to choose any other occuption than their fathers'. The same thing is true when people vote someone into office as he or she meets the demands to be their representative.
（扩展到all occuptions）
people earn a reputation on merit, not their birth or wealth. The poor can climb out of poverty by industry, talent and clear head, while the rich cannot guarantee their offspring the same privilege they have enjoyed.（贵族制度影响，没介绍清楚，扩展太多）
Therefore, every person is given the chance to achieve success, as long as he has the brains and perseverance required. be it a son of lawmaker or of a shoemaker. （by birth概括）One of the greatest president in our nation’s history, Abraham Lincoln, who has risen all the way up to the highest rank in our country, is a true testament to what a man of humble birth can achieve from scratch.
