To obtain accuracy in fixing by DF，（）and three stations should be used.
A. parallel bearings
B. long-range bearings
C. short-range bearings
D. cross bearing
金属材料由于化学成分不均匀，在电解液中发生（）腐蚀。
A. 化学
B. 宏观电化学
C. 微观电化学
D. 氧浓差
Which two statements about the IS -IS routing protocol are true?（）
A. IS - IS is capable of supporting IPv4 and IPv6.
B. IS - IS is only capable of supporting IPv4 and CLN
C. IS - IS routers use ES - IS hellos (ESH) to establish and to maintain neighbor relationships.
D. IS - IS routers run the Bellman - Ford algorithm against their LSDBs to pick the best paths.
E. Level 1 routers learn about paths within the area of which they are a part.
F. Level 2 routers learn about paths both within areas and between areas.
胡锦涛同志在十八大报告中提出，在（）中加强社会建设
A. 改善民生和创新社会管理
B. 深化改革和创新管理
C. 在发展经济和改善民生
D. 改善民生和创新管理
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