题目内容：
阅读文章，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 early1890s．Jazz is America’s contribution to_______ （4）music．In contrast to classical music，which_______ （5）formal European traditions jazz is spontaneous and free in form．It bubbles 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 to carry to body to the cemetery．In New Orlearts，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 number，but the living were glad to be_______ （13）．The band played_______ （14）music，improvising 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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