(71) analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system models become the (72) for designing and constructing an improved system. (73) is such a technique. The emphasis in this technique is process-centered. Systems analysts draw a series of process models called (74) 、 (75) is another such technique that integrates data and process concerns into constructs called objects.

（71）应选（）。

A．Prototyping

B．Accelerated

C．Model-driven

D．Iterative

三个或三个以上的音，按一定关系叠置起来，叫做（）。