从经济学的角度看,二部定价的优点有( )
A.价格结构简单,计收简便
B.是一种次优定价选择
C.满足企业收支平衡约束
D.排挤低消费用户
E.资费方式多样
参考答案:B,C,E
We have friends ____, though we are a developing country. [ ]
A. all the same
B. all the time
C. all our lives
D. all over the world
慢性肾盂肾炎主要辅助检查项目应是
A.双肾B超B.双肾CTC.静脉肾盂造影D.肾活检