单项选择题
A.spanning-tree mode rapid-pvst
B.spanning-tree uplinkfast
C.spanning-tree backbonefast
D.spanning-tree mode mst
多项选择题 Whichtwoaddressescanbeassignedtoahostwithasubnetmaskof255.255.254.0？（）
单项选择题 When two hosts are trying to communicate across a network, how does the host originating thecommunication determine the hardware address of the host that it wants to "talk" to?（）
单项选择题 Which network protocol does DNS use?（）