听力原文：The 1950s and 1960s were years of great struggle for black Americans. Although slavery had been abolished in 1863, segregation in the 1950s -- the separate and unequal treatment of blacks by whites -- was still the custom in the northern part of the United States. In the southern states it was the law. As an example, suppose you were a black citizen in Montgomery, Alabama, in 1954. A simple bus ride into town could be very frustrating. When the bus stopped for you, you paid the driver in the front of the bus. However, as a black person, you were not allowed to sit in the front. The front was for whites only. So, after paying the driver, you had to get off the bus, walk to the back, enter at the rear door, and sit down in the back. What happened if the front of the bus was full and more white passengers got on? Well, you had to give up your seat in the back and ride standing. That was the law. On Thursday, December 1, 1955, something important happened. On the day, Mrs. Rosa Parks, a middle-aged black woman, refused to give up her seat to a white man. The bus driver called the police and she was arrested. This one small event helped change the direction of American history. It also marked the beginning of the career of the most famous black American leader. Martin Luther King, Jr.. Dr. Martin Luther King, Jr. was a young minister in a black church in Montgomery. When he heard about Mrs. Park's arrest, he, along with other black leaders in the city, decided to protest it. They organized a boycott of the buses for one day. That is, every black person in Montgomery was asked to stay off the buses for one full day. The boycott was a complete success. Because about 70% of the bus company's customers were black, the buses drove almost empty all day long. Later that day, black leaders decided to continue the boycott until the company promised black riders better treatment. As the boycott went on with Dr. King as its leader, the white people of Montgomery became more and more upset and angry. Dr. King was put in jail and beaten, and his house was bombed. But throughout all this, Martin Luther King told his people to 'meet violence with nonviolence' and to 'meet hate with love'. Because of his powerful message of nonviolence, no one was killed during the entire year of boycott. Finally, in 1965 the linked States Supreme Court said it was illegal to segregate blacks and whites on buses, trains, or planes. Martin Luther King had taught his people a new way to win their rights. After the bus boycott, the use of nonviolence protest against segregation became popular throughout the South. Dr. King led many peaceful marches against segregation in restaurants, movie theaters, and other public places. On August 28, 1963 the biggest march of ail was held. More than a million people from all parts of the country, black and white, young and old, marched on Washington, D. C.. They wanted Congress to pass a national law against segregation and discrimination. Two days after Dr. King gave his famous speech, one of his goals was achieved. The Civil Rights Act of 1964 became a new law that made it illegal to segregate blacks or other minorities or discriminate against them. In the same year, Martin Luther King also received the Nobel Peace Prize. His work was far from finished, however. He continued to fight for civil rights not only in the South but also in northern cities like Chicago and Detroit, which had large numbers of unemployed black workers. His message was still one of nonviolence although some young black leaders no longer accepted it as a way to win equality. In 1968 violent riots broke out in New York, Detroit, and Los Angeles, poisoning the air of the country with hatred and violence. The horrible climax came on April 4, 1968, when Martin Luther King, Jr. was shot to death by a white man. Thanks to Dr. King and the civil rights movement, black Americans and other minorities have won many rights in the last