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问题 单项选择题 案例分析题

某架空送电线路，有一档的档距1=1000m，悬点高差h=150m，最高气温时导线最低点应力为50N/mm2，垂直比载γ=25×10-3N/（m·mm2）。

用斜抛物线计算最大弧垂为（）。

A.62.5m

B.63.2m

C.65.5m

D.61.3m

答案

参考答案：B

单项选择题

Basically, a (71) is a standalone process or a set of integrated processes that runs on a router or server to control the flow of (72) application traffic (73) through it. Typically, firewalls are (74) on the entry point to a public network such as the Internet. They could be considered traffic cops. The firewall’ s (75) is to ensure that all communication between an organization’s network and the Internet conform to the organization’s security policies.

72（）

A．network

B．networked

C．net

D．networky
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单项选择题

根据增值税法律制度的规定，下列出口货物中，不免税也不退税的是( )。

A．国家计划外出口的原油

B．国家出口计划内的卷烟

C．企业在国内采购并运往境外作为在国外投资的货物

D．来料加工复出口的货物
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