The American Revolution was a citizens revolution. Ordinary men took a large part in it. One of them was Paul Revere, a silver worker. He lived in Boston many years ago during the time when many people in the British colonies in America felt that they were being used for Britains gain. They felt that they were being taxed without fair representation in the British government. The people of Boston were especially angry, and additional British troops had been sent there to keep the excited colonists under control. Paul Revere was one of those who believed that the British would soon be on the march against the villages and farms near Boston. On the night of the eighteenth of April, 1775, Revere rowed across the Charles River to a place opposite Boston where his saddled horse was ready to ride. If the British soldiers came, he was to ride to warn the people. A friend in Boston was hidden near the British troops in a place where he could watch what they did. If they marched by land, he was to hang one lantern (灯笼) high in the tower of the old North Church in Boston where Paul could see it. If they came by sea, he would hang up two lanterns. Toward morning Revere saw two lights in the tower. The British must be coming by sea! He jumped on his horse and rode through the countryside before dawn in order to warn the farmers and villagers that they must fight at the daybreak. He rode all night and in the morning, by the time the troops arrived, the farmers were hidden all along the roads with their guns loaded. When the British came, the Americans drove them back. These first battles of the American Revolution were fought at Concord and at Lexington, Massachusetts, on April 19, 1775. In 1776 the colonies signed a declaration of independence. What is the authors main purpose in the passage?