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问题 单项选择题

纵联保护应优先采用（）。双回线路采用同型号纵联保护，或线路纵联保护采用双重化配置时，在回路设计和调试过程中应采取有效措施防止保护通道交叉使用。分相电流差动保护应采用同一路由收发、往返（）的通道。

A.光纤通道交叉

B.高频通道延时一致

C.光纤通道交叉

D.光纤通道延时一致

答案

参考答案：D

单项选择题

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) .

75（）

A．activity diagram

B．component diagram

C．sequence diagram

D．state diagram
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单项选择题

下列不是酸蚀的作用的有（）

A.暴露清洁新鲜的釉质

B.活化釉质表层

C.增大牙齿表面积

D.除去釉质表面玷污层

E.保护牙髓活力
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