下列哪些物质可促进药物经皮吸收（）
A.油酸
B.丙二醇
C.月桂氮革酮
D.尿素
E.三聚氰胺
参考答案：A, B, C, D
Which of the following statement about the normal distribution is FALSE()
A. It is completely described by its mean and standard deviation.
B. It has a skewness of 1.
C. It is bell-shaped.
有关提高企业服务质量的方法，比较常用的有（）。
A、标准跟进
B、流程图
C、结构重整
D、蓝图技巧
