The operation of the Internet is closely monitored by the routers. When something unexpected occurs, the event will be reported by the protocol (73) 。

A．IGMP

B．ICMP

C．IP

D．OSPF

以个人和社会网络连接的紧密程度不同来区分，社会网络可以分为

A．稳固形态和松散形态

B．互利形态和互补形态

C．封闭形态和开放形态

D．过程形态和结果形态