阻塞性黄疸时引起皮肤瘙痒的主要物质是()
A.非酯性胆红素
B.酯性胆红素
C.胆固醇
D.胆汁酸盐
E.磷脂
参考答案:D
解析:主要由胆汁酸盐引起皮肤瘙痒。
There is _______ report in today's newspaper. It's about _______ sports meeting that will be held in Weihai.
A. a; the
B. an; the
C. the; the
D. a; a
总体经过分类后,若类内方差较大而类间方差较小,则适用于()。
A.简单随机抽样
B.分类抽样
C.整群抽样
D.等距抽样