课堂问题行为
ZXAN#write该命令将同时保存（）GCSA。 ["主用","备用","主备用","线板"]
Which two statements are characteristics of a distance vector routing protocol?（） [" RIP is an example of distance vector routing protocols."," Updates are periodic and include the entire routing table."," Routing updates are sent only after topology changes"," The protocol can be useful in hub-and-spoke and hierarchical networks."," Convergence is usually faster than with link state protocols"," Each router has its own view of the topology"]
熙宁二年，苏辙《上皇帝书》说凡今农、工、商贾之家，未有不舍其旧而为士者也。”这表明（）。 ["唐代四民界限模糊","唐代商品经济繁荣","宋代小农经济衰落","宋代科举制的发展"]
现代教学手段的多媒体化
密度梯度的制备方法有（）、（）、（）、（）。
