为什么使用代理服务器可以节省连入Internet的IP地址？
（）VLAN能充当中继链路两端的公共标识。 ["本征","数据","语音","默认"]
桩承载力检测常用的方法有（）。 ["动力参数法","声波透射法","抽芯法","静载试验"]
（）是物质因状态或压力发生突变而形成的爆炸，如锅炉爆炸.压缩气体.液化气体超压引起的爆炸。 ["物理性爆炸","化学性爆炸","一般性爆炸"]
Routers R1 and R2 are OSPF neighbors using their Fa0/0 interfaces, respectively, using default settings for all timers. An engineer ad ds the ip ospf hello - interval 6 command to R1's Fa0/0 configuration. Which of the following is true regarding the results from this change?（） [" The show ip ospf neighbor command on R1 lists the revised Hello timer"," The show ip ospf interfac e brief command on R1 lists the revised Hello timer"," The R1 - R2 neighborship fails due to Hello timer mismatcH"," The show ip ospf interface command on R1 lists the revised Hello timer"]
对比几种不同的网络接入方式列出它们的有缺点
