市场调查中,一个问题有多种答案的情况很常见,多项选择题就属于这种情况。
参考答案:对
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
采用预制封隔器及预制充填砾石完井法时,在下入管柱前钻井液要转化为完井液,且无固相或是暂堵型固相,其粒度为孔喉直径的()。
A.1/8~1/6
B.1/6~1/2
C.1/3~1/2
D.1/2~2/3