Many of the activities performed during the preliminary investigation are still being conducted in (1) , but in much greater depth than before. During this phase, the analyst must become fully aware of the (2) and must develop enough knowledge about the (3) and the existing systems to enable an effective solution to be proposed and implementeD. Besides the (4) for process and data of current system, the deliverable from this phase also includes the (5) for the proposed system.

5（）

A．hardware and software specification

B．system performance specification

C．formal requirements definition

D．general problem statement

下列可确定诊断霍乱的是（）

A.有吐泻症状，便培养阳性

B.无症状但便培养阳性，粪便检查前后5天出现腹泻症状，有密切接触史

C.流行期间有明显接触史，且有无理由解释的吐泻症状，

D.流行地区人群，有典型症状，便培养阴性，血清凝集抗体测定效价呈4倍或以上增长

E.有典型症状无病原学检查