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）处填（）。

A．use-case modeling

B．class modeling

C．dynamic modeling

D．behavioral modeling

下列变化中，不需要破坏化学键的是（　　）

A．氯化氢溶于水

B．浓硝酸见光分解

C．冰雪融化

D．氯化钠熔化