Which two are characteristics of the IS -IS protocol but not OSPF?（）
A. forms adjacencies with all neighbors
B. supports demand circuit routing
C. provides routing support for multiple network layer protocols
D. utilizes SPF algorithm
E. provides for network scalability by allowing the network to be separated into areas
F. three layers of hierarchical routing
查看答案
各级机关和大队、中队通常（）举行1次升国旗仪式，“八一”、“十一”等重大节日和本部队纪念日应当隆重举行升国旗仪式。
以慈禧为首的顽固派认为维新变法只能救国，不能救大清。
A. 正确
B. 错误
水下电焊可以采用直流和交流电源。
A. 正确
B. 错误
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