I would have gone to visit him in the hospital had it been at all possible, but I_______ fully occupied the whole of last week.

A．were

B．had been

C．have been

D．was

参见下图的网络配置，客户机无法访问服务器，原因是什么？（）。

A.服务器的IP地址是广播地址

B.客户机的IP地址是子网地址

C.客户机与默认网关不在同一子网中

D.服务器与默认网关不在同一子网中