Part of the routing table of router R1 is displayed below： S 62.99.153.0/24 [1/0] via 209.177.64.130 172.209.12.0/32 is subnetted， 1 subnets D EX 172.209.1 [170/2590720] via 209.179.2.114， 06：47：28， Serial0/0/0.1239 62.113.17.0/24 is variably subnetted， 2 subnets， 2 masks D EX 99.3.215.0/24 [170/27316] via 209.180.96.45， 09：52：10， FastEthernet11/0/0 [170/27316] via 209.180.96.44， 09：52：10， FastEthernet11/0/0 25.248.17.0/24 [90/1512111] via 209.179.66.25， 10：33：13， Serial0/0/0.1400001 [90/1512111] via 209.179.66.41， 10：33：13， Serial0/0/0.1402001 62.113.1.0/24 is variably subnetted， 12 subnets， 2 masks D 62.113.1.227/32 [90/2611727] via 209.180.96.45， 10：33：13， FastEthernet1/0/0 [90/2611727] via 209.180.96.44， 10：33：13， FastEthernet1/0/0 S* 0.0.0.0/0 [1/0] via 209.180.96.14 From analyzing the above command output， what is the administrative distance of the externalEIGRP routes？（） ["24","32","90","170","27316","None of the other alternatives apply"]
水轮机顶盖上为什么要装真空破坏阀？其作用是什么？
某企业只生产一种产品，单位变动成本为36元，固定成本总额4000元，产品单位售价56元，要使安全边际率达到50%，该企业的销售量应达到（）。
进行保险经济活动所应具备的基本条件是（）。 ["大量同质风险的集合与分散","可保风险的存在","保险费率的厘定与保险基金的建立","保险合同的订立"]
Which two statements about Network Attached Storage are correct?（） [" Data is accessed using NFS or CIFS."," Data is accessed at the block level."," NAS is referred to as captive storage."," Storage devices can be shared between users."," A NAS implementation is not as fast as a DAS implementation."]
结合中国农村人口问题，评述托达罗“人口流动模型”。
