结合实际，谈一谈学生应如何履行《中华人民共和国教育法》中所规定的学生的义务。
试述在箱体镗削加工中，第一道工序粗基准的选择原则。
Multicast is being deployed in the network， and only ip pim sparse-dense mode has been configured on allinterfaces in the network to support a new video streaming application. No other multicast configuration wasapplied anywhere in the network. Since enabling multicast， the network monitoring tools show periodic spikes in link utilization throughout the network， even in areas where the video application is not being used.What could be a possible cause？（） ["PIM sparse mode is being used.","PIM dense mode is being used.","The BGP multicast address family has not been configured.","IGMP version 3 is being used.","IP PIM neighbor filters have not been applied."]
You use OSPF as your network routing protocol. You use the command show ip route and you see several routes described as O， O IA， O E1， and O E2. What routes are in your area？（） ["O IA","O E1","O E2","O"]
在采掘工程平面图上，某段巷道各测点的标高数值相差很大，则可断定该巷道为：（）。 ["平巷","斜巷","立井","不能判定"]
简述班集体形成的过程。
