结构化分析方法最后提供的文档是软件的( )。
A.结构说明书
B.加工说明书
C.需求说明书
D.可行性报告
参考答案:C
试述DK-1型电空制动机与主断路器的配合作用?
All mammals have hair, but not always evident.()
A. but it is not
B. but it is
C. but they are not
D. but they are