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

在设备采购合同履行中，还应对供应商按照设备采购合同规定为设备调试提供的备品配件进行查验，并督促其在设备调试期间提供一定的( )。

A．技术支持

B．调试讲解

C．口头指导

D．技术支持和服务