缓冲溶液是指（）
A.具有抗酸成分的溶液
B.具有抗碱成分的溶液
C.含有弱酸成分的溶液
D.含有弱碱成分的溶液
E.具有缓冲作用的溶液
参考答案：E
批复是答复下级请示的文件，是( )。
A．被动发文
B．主动发文
C．是对报告的批件
D．下级没有请示，用来指导工作的
Price discrimination is most accurately defined by which of the following Price discrimination is the practice of charging different consumers different prices for:（）
A. similar products that have identical per-unit production costs.
B. products that have identical price elasticities of demand.
C. the same product or service.
