My sister _____ as a secretary in her company for three years and now she _____ to

the manager of the sales department. [ ]

A. served; has been promoted

B. had served; has been promoted

C. has served; has promoted

D. was serving; has promoted

数据流图用于抽象描述一个软件的逻辑模型，数据流图由一些特定的图符构成。下列图
符名标识的图符不属于数据流图合法图符的是

A．控制流

B．加工

C．数据存储

D．源和潭