物流系统中存在着哪些制约关系？

工作总量一定，工作效率和工作时间成反比例．______．

Things have changed quickly over the past decade and life in the country is much better than _____ used to be. [ ]

A. that

B. it

C. what

D. one

Use the following information to determine the value of River Gardens' common stock:
Expected dividend payout ratio is 45 percent.
Expected dividend growth rate is 6.5 percent.
River Gardens' required return is 12.4 percent.
Expected earnings per share next year are $3.25.（）

A. $27.25.

B. $24.80.

C. $19.67.

某企业于2002年9月接受一项产品安装任务，安装6个月，合同总收入20万元，年度预收款项9万元，余款在安装完成时收回，当年实际发生成本6万元，预计还将发生成本4万元。则该企业2002年度确认收入为( )万元。

A．8

B．12

C．20

D．0