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) .

（73）处填（）。

A. use-case modeling

B. class modeling

C. dynamic modeling

D. behavioral modeling

以下对电子通关的有关表述，正确的是（）

A．电子通关是指检验检疫机构签发的通关单的电子数据传输到海关计算机业务系统，海关将报检报关数据比对确认相符合，予以放行

B．电子通关单联网核查系统由国家质检总局和海关总署开发。

C．2003年1月1日起，在主要口岸的检验检疫机构和海关采用网络信息技术实行电子通关。

D．目前电子通关模式是，检验检疫机构和海关联合采取通关单联网核查系统，但未完全行无纸化报关，仍需同时校验纸质的通关单据