A new floor has been added to the enterprise campus network， providing client access for desktop PCs， laptops， and IP phones for employees and guests. During verification， a few desktop PCs have limited corporate access but not Internet access. Most other desktop PCs， all laptops， and IP phones are working correctly. Additional information indicates that the desktop PCs are obtaining IP host addresses from the DHCP server， which is intended for only the IP phones. Where should troubleshooting about this connectivity issue be focused？（） ["DNS","first-hop redundancy protocol","DHCP server and options","VLAN mapping","client network configuration","routing protocol"]
发动机与气相位影响着发动机的动力特性及经济特性，优秀发动机的配气相位是随转速、负荷的变化而自动改变（）的大小来适应发动机需要的。 ["点火时刻","喷油时刻","喷油延续角","配气相位角"]
中国共产党是中国工人阶级的先锋队，同时是中国人民和中华民族的先锋队。
违反民主集中制原则，（）或（）党组织作出的重大决定，或者违反议事规则，个人或者少数人决定重大问题的，给予警告或者严重警告处分。 ["拒不执行","擅自改变","决意违反","打折扣落实"]
旅客运输生产向社会提供的是无形产品―（）。
VPN的部署方案有几种？各有什么特点？
