铁路站线包括（）等几种类型。 ["到发线、调度线、货物线、专用线","到发线、调度线、工业企业线、正线","牵出线、到发线、调车线、段管线","到发线、调车线、货物线、牵出线"]
Before inserting a new switch in the network， the network administrator checks that the VTP domain name is correct， the VTP mode is set to server， and revision is lower than the switches in the network. The administrator then configures interfaces and trunks， erases existing VLANs， and connects the switch to the network. Following that procedure， there is no connectivity in the network. What is a possible cause of this problem？（） ["Because the configuration revision of the new switches is lower than the rest of the network， it can change the VLAN database of the other switches.","As a VTP server， the new switch deleted all VLANs of the network.","Erasing VLANs increases the VTP configuration revision.","Since the configuration revision of the network is higher than the new switch， the VLAN database was automatically synchronized."]
《动车组列车服务质量规范》遇火灾爆炸、重大疫情、食物中毒、空调失效、设备故障和列车大面积晚点、停运、变更径路、启用热备车底等非正常情况时，及时启动应急预案，掌握车内旅客人数及到站情况，维持车内秩序，准确通报信息，做好咨询、解释、安抚、生活保障等善后工作。
变速器（）齿轮或吃套牙齿磨成锥形。 ["跳档","空挡","换挡","调档"]
乘务人员未按规定使用定位卡，属于（）问题。 ["红线","A1","A2","B"]
问ip precedence有几个bit？
