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 determines 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）.

（74）处填（）。

A．use-case modeling

B．class modeling

C．dynamic modeling

D．behavioral modeling

不是慢性呼吸衰竭患者机械通气指征的为（）

A.PaCO₂升高达到60mmHg以上

B.并发肺性脑病

C.PaCO₂进行性升高

D.呼吸频率超过35次／分

E.严重的低氧血症，积极氧疗后，PaO₂仍<40mmHg