预算定额的编制应反映( )。
A．社会平均水平 B．社会平均先进水平C．社会先进水平 D．企业实际水平
参考答案：A
设关系R和关系S的元数分别是3和4，关系T是R与S的广义笛卡尔积，即：T=R× S，则关系T的元数是
A．7
B．9
C．12
D．16
The distress message of a ship should include considerable information which might facilitate the rescue. This information should（）.
A.ALWAYS be included in the initial distress message
B.be sent to a Coast Guard station FIRST
C.be transmitted as a series of short messages，if time allows
D.include the vessel's draft
