Which statement about the preliminary design stage of a software development project is true ______

A．The preliminary design is an internal document used only by programmers

B．The preliminary design is the result of mapping product requirements info software and hardware functions

C．The preliminary design of the product comes from the requirement specification

D．The developers produce the preliminary design by defining the software structure in enough detail to permit coding

肝硬化、门脉高压时，腹壁静脉血流方向为（）

A．脐水平以上静脉血流向上，脐以下血流向下

B．脐以上水平静脉血流向下，脐以下血流向上

C．腹壁静脉血流全部向上

D．腹壁静脉血流全部向下

E．以脐为中心血流向四周