单项选择题
A、所有线缆都可以 B、屏蔽双绞线1类线 C、非屏蔽双绞线四类线 D、非屏蔽双绞线五类线
A、ping B、tracert C、route D、netstat
A.255.254.0.0 B.255.255.252.0 C.255.255.248.0 D.255.192.0.0