问题
单项选择题
In software engineering and systems engineering, (71) is a description of a system's behavior as it responds to a request that originates from outside of that system．
A．black box
B．business rule
C．use case
D．traceability matrix
答案
参考答案：C
解析：[分析] 在软件工程和系统工程中，用例是一种描述系统的特征，作为反应外界请求的描述。