It is difficult to say exactly how the music we call “rock” or “rock and roll” began. Its roots (根源) go back to many different countries and many different kinds of music and many musicians.
Rock music developed mainly from the interaction (相互影响）of black African and white European music. The Europeans and the African slaves (奴隶）who came to America during the seventeenth century each had their own different kinds of music. Black Africans used heavy drumbeats，a rough singing voice，and the calling of a melody (旋律）and answer of a chorus. The white Europeans，mostly English and Scots，used a stronger melody，a less heavy beat，and instruments such as guitars，horns，and fiddles. The history of rock and roll is the history of how rock changed from these two traditions.
From the seventeenth to the twentieth century， musicians in the southern United States developed two new forms of music： the blues，usually played by blacks，and country music， played by whites. Black musicians sang the blues with a guitar. This music was similar to work songs：stories of troubles and pain， with lines that were repeated several times. The word “rock and roll” probably came from the black churches in the South， where people sang and danced to the strong rhythms， which they called “rocking and reeling”. At the same time， whites were playing country music， which was mostly traditional dancing music and slow songs that told sad stories. The singers played with string instruments such as fiddles and guitars.
During this time blues and country musicians had some influence on each other， but the influence grew stronger after phonograph records (留声机唱片)became popular in the late nineteenth century. The birth of the electric guitar changed country and blue music in the 1940s. The sound of the electric guitar would become the sound， of rock and roll. No one thinks of early rock and roll without thinking of Elvis Presley，the“King of Rock and Roll”.Rock music continues to develop and change， but the heart and soul of rock is the same heart and soul that Elvis expressed.
What’s the best title for the passage?

A．Different Kinds of Music

B．The Beginning of Rock and Roll

C．Elvis’s Contribution (贡献）to Music

D．Rock and Roll Is Developing

Which of the following doesn’t describe black Africans’ music style?

A．They used heavy drumbeats.

B．They sang in a rough voice.

C．They used instruments such as guitars， horns， and fiddles.

D．They used the calling of a melody and answer of a chorus.

Which of the following describes country music?

A． Country music is usually played by blacks.

B．People sang spiritual music and danced to the strong rhythms， which they called “country music”.

C．Country music was traditional dancing music and slow songs that told sad stories.

D．Country music was similar to work songs.

Which of the following NOT right according to the passage?

A．In the seventeenth century， many visitors went to America from Europe and Africa.

B．Rock music developed mainly from the interaction of black African and white European music.

C．Musicians in the southern United States developed two new forms of music： the blues and country music from the seventeenth to the twentieth century.

D．Blues and country musicians had some influence on each other during a time in history.