As far as I know this is a type of music popular in the 1950s a(n) of jazz and folk mus

问题补充：

As far as I know, this is a type of music popular in the 1950s, a(n) of jazz and folk music.

A. mixture

B. tradition

C. practice

D. invention

答案：

(答案→)A. mixture

B. tradition

C. practice

D. invention

解析：考查名词辨析。A混合物；B传统；C锻炼，做法；D发明；句意：据我所知。这是一种在20世纪50年代很流行的音乐，一种爵士乐和民间音乐的混合音乐。