构筑物流系统的主要成本因素是( )。
A．人员工资
B．物流技术及其装备费用
C．装卸成本
D．仓储成本
参考答案：B
Words failed her when the _____ mother wanted to express her thanks to the policeman who had
saved her son. [ ]
A. upset
B. grateful
C. confident
D. sensitive
引起内伤咳嗽的主要原因是（）
A.肺脏虚弱
B.脾失健运
C.肝火犯肺
D.肾脏亏虚
E.心火亢盛
