固定制造费用产量差异是根据预算产量下的标准工时与实际产量下的标准工时的差额，乘以固定制造费用标准分配率计算得出的。( )
参考答案：错
一体化机车信号主机接收信息从其他制式转为移频或ZPW-2000（UM71系列）时，信号显示的应变时间不大于（）秒。
A.0.5
B.1.5
C.2
D.4
Object-oriented analysis(OOA)is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is (71) . It determines how the various results are computed by the product and presents this information in the form of a (72) and associated scenarios. The second is (73) ，which determines the classes and their attributes. Then determine the interrelationships and interaction among the classes. The last step is (74) , which determines the actions performed by or to each class or subclass and presents this information in the form of (75) .
73（）
A．use-case modeling
B．class modeling
C．dynamic modeling
D．behavioral modeling
