连锁物流配送中心的信息系统一般分为（）
A.流通层
B.交易层
C.管理层
D.决策层
E.战略层
参考答案：B, C, D, E
I like to lie _____________ the grass in summer. [ ]
A. in
B. on
C. at
Which of the following are NOT considered important in defining an urban area
A．Political boundaries.
B．Transportation networks.
C．Social relationships.
D．Economic systems.
