A．it is the printed version of standardized folk music
B．it encourages people to popularize printed versions of songs
C．it tends to standardize folk songs when it is used by folk musicians
D．it has a great effect on the music-culture as more and more people are able to read it

A．It is a small amount to pay for so much precious metal.
B．It is difficult to judge the value of such an object.
C．It is reasonable for an object with such an important function.
D．It is too high for such a light weight.