A network is composed of several VRFs. It is required that VRF users VRF_A and VRF_B be able to route to and from VRF_C， which hosts shared services. However， traffic must not be allowed to flow between VRF_A and VRF_B. How can this be accomplished？（） ["route redistribution","import and export using route descriptors","import and export using route targets","Cisco MPLS Traffic Engineering"]
不属于人力换档变速器的优点是（） ["结构简单","工作可靠","动力切断所需时间短","传动效率高"]
动车组2车客室内设有吸烟处。
基因工程
《生产安全事故调查规程》中规定人员设备事故应查明哪些内容？
净现值有哪些特点？
