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) .

（74）处填（）。

A．use-case modeling

B．Glass modeling

C．dynamic modeling

D．behavioral modeling

航空活塞发动机要降低发动机汽缸头温度，除减少发动机功率和增加空速之外，较有效的办法还有（）.

A.增大滑油散热器风门的开度

B.减小发动机的转速

C.操纵混合比杆，使混合气适当变富油