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) .

（71）处填（）。

A. static modeling

B. dynamic modeling

C. use-case modeling

D. behavioral modeling

测定环境水样中的氟首选的仪器分析方法是（）

A、GC

B、ISE

C、AAS

D、UV