What do you hear when you go into a store or a supermarket? Soft music is playing in the background. It's similar to the music you listen to, but it's not  the same. That is because this music was designed to relax you or give you extra . Sometimes you don't even realize the music is playing, but you react to the music anyway.

    Quiet background music used to be called "elevator(电梯) music" because it was  played in elevators. But now we hear it in more and more public places such as a railway station or a . And now it has a new name "Muzak". About one-third of the people in America listen to "Muzak" every day. The music plays for 15 minutes at a time.