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) .

（72）处填（）。

A．collaboration diagram

B．sequence diagram

C．use-case diagram

D．activity diagram

救生艇内外均应涂（）。

A、白漆

B、红漆

C、橙黄色漆