Rock and roll is a genre of popular music that evolved in theUnited Statesin the late 1940s and early 1950s. Its  1  lie mainly in blues, rhythm and blues, country, folk, gospel, and jazz. The style subsequently spread to the rest of the world and developed further, leading ultimately to 2  rock music.

　　The term “rock and roll” now covers at least two different meanings, both in common usage. The American Heritage Dictionary and the Merriam-Webster Dictionary both 3  rock and roll as synonymous with rock music.

　　4  , Allwords.com defines the term as referring specifically to the music of the 1950s.

　　Classic rock and roll is 5  played with one or two electric guitars, a string bass or an electric bass guitar, and a drum kit. In the 6 rock and roll styles of the late 1940s, either the piano or saxophone was often the lead instrument, but these were generally 7  or supplemented by the guitar in the middle to late 1950s.

　　The massive popularity and eventual worldwide view of rock and roll gave it a 8  social impact. Far beyond simply a musical style, rock and roll, as seen in movies and in the new medium of television, 9  lifestyles, fashion, attitudes, and language. It went on to spawn various sub-genres, often without the initially 10 backbeat, that are now more commonly called simply “rock music” or “rock”.

A. define      
B. characteristic 
C. unique

D. roots
E. usually 
F. Basically　  
G. earliest    
H. influenced
 I. followed  
J. modern
K. explanation    
 L. Conversely

M. replaced    
N. prepare

 O. seld