电焊机二次线长度不应超过(),必须采用防水橡皮护套铜芯电缆。
A. 5m
B. 10m
C. 20m
D. 30m
How are IP multicast IGMP entries synchronized between vPC peers?()
A. IGMP is not synchronized between vPC peers
B. Cisco Fabric Service carries IGMP entries across the vPC peer link
C. IP ARP synchronization under the vPC domain configuration also synchronizes IGMP
D. IGMP is flooded to the L2 domain, and there is no need to synchronize it between vPC peer
顽固性根尖周病变和窦道经久不愈,可能与下列哪种细菌感染有关()
A. 放线菌
B. 牙龈卟啉单胞菌
C. 消化链球菌
D. 产黑色素普氏菌
E. 真菌
降低杆塔接地电阻是提高线路耐雷水平防止直击雷的有效措施。()
A. 正确
B. 错误