题目内容：
根据下面短文内容，回答题。An Early Form of Jazz Music
Music comes in many forms; most countries have a style of their own. At the turn of the last century, __________ (1) jazz was born. America had no prominent __________ (2) of its own. No one knows exactly when was invented or by whom. But it began to be__________(3) in the early 1890s. Jazz is America's contribution to __________ (4) music. In contrast to classical music, which__________(5) formal European traditions, jazz is spontaneous (自发的) and free in form. It bubbles( 充满)with energy, __________(6) the moods, interests, and emotions of the people. In the' 1920s jazz __________ (7) like America. And so it does today. The__________(8) of the music are as interesting as the music itself. American Negroes, or blacks, as they are called today, were the jazz pioneers. They were brought to the Southern states __________ (9) slaves. They were sold to plantation owners and forced to work long hours. When a Negro died his friends and relatives__________(10) a procession( 队列，队伍)to carry to body to the cemetery. In New Orleans, a band often accompanied the__________(11). On the way to the cemetery the band played slow, solemn music, suited to the occasion. (12) on the way home the mood changed. Spirits lifted.
Death had removed one of their members, but the living were glad to be __________ (13). The band played __________ (14) music, improvising ( 即兴) on both the harmony and the melody of the tunes__________(15) at the funeral. This music made everyone want to dance. It was an early form of jazz.
____________ A．while
B．when
C．since
D．as
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