三.阅读理解(40分) Americans have contributed to many art forms, but jazz, a type of music, is the only art form that was created in the United States. Jazz was created by black Americans. Many blacks were brought from Africa to America as slaves. The black slaves sang and played the music of their homeland. Jazz is a mixture of many different kinds of music. It is a combination (合并) of the music of west Africa, the work songs the slaves sang, and religious music. Improvisation(即兴创作)is an important jazz. This means that the musicians make the music up as they go along, or create the music on the spot. This is why a jazz song might sound a little different each time i t is played. Jazz bands f ormed in the late nineteenth century. They played in bars and clubs in many towns and cities of the South, especially in New Orleans. New Orleans is an imitational seaport, and people from all over the world come to New Orleans to hear jazz. Jazz became more and more popular. By the 1920s, jazz was popular all over the United States. By the 1940s, you could hear jazz not only in clubs and bars, but in concert halls as well. Today, people from all over the world play jazz. Jazz musicians from the United States, Asia, Africa, South America, and Europe meet and share their music at festivals on every continent. In this way, jazz continues to grow and change. 1．From the passage we know that_____________created jazz. A．white American B．black Americans C．West Africans       D．Indian Americans 2．What is the main idea of this passage? A．It mainly tell about the contributions made by Americans to music. B．It is mainly about different kinds of music. C．It is about how jazz bands formed. D．It is mainly about the history of jazz. 3．It can be known from the passage that jazz bands have a history of_________. A．about 100 years       B．around 200 years C．about 150 years       D．around 250 years 4．What kind of characteristics does jazz have? A． It is always changing. B．It is only played in the United States. C．It is completely different from other music. D．It is played in bars, clubs and concert halls.