单项选择题
A. SW1（config-if）# switchport trunk encapsulation dot1q SW1（config-if）# switchport mode trunk SW1（config-if）# switchport trunk native DATA SW1（config-if）# switchport trunk allowed vlan 1，10，20
B. SW1（config-if）# switchport trunk encapsulation dot1q SW1（config-if）# switchport mode dynamic auto SW1（config-if）# switchport trunk native DATA SW1（config-if）# witchport trunk allowed vlan add 1，10，20
C. SW1（config-if）# switchport trunk encapsulation dot1q SW1（config-if）# switchport mode dynamic desirable SW1（config-if）# switchport trunk native vlan DATA SW1（config-if）# switchport trunk allowed vlan 1，10，20
D. SW1（config-if）# switchport trunk encapsulation dot1q SW1（config-if）# switchport mode dynamic desirable SW1（config-if）# switchport trunk native vlan 10 SW1（config-if）# switchport trunk allowed vlan 1，10，20
E. SW1（config-if）# switchport trunk encapsulation dot1q SW1（config-if）# switchport mode dynamic Desirable SW1（config-if）# switchport trunk native vlan 10
单项选择题 You need make configuration changes to an existing layer 3 switch in the Company network. On a multilayer Catalyst switch， which interface command is used to convert a Layer 3 interface to a Layer 2 interface？（）
单项选择题 Refer to the exhibit. The user who is connected to interface FastEthernet 0/1 is on VLAN 10 and cannot access network resources. On the basis of the information in the exhibit， which command sequence would correct the problem？（）
单项选择题 Refer to the exhibit. Switch S2 contains the default configuration. Switches S1 and S3 both have had the command spanning-tree mode rapid-pvst issued on them. What will be the result？（）
