Ruby是一个非常有用、非常强大的工具，是每个系统管理员工具箱中必备的工具。
Ruby is a very useful and powerful tool that is a must-have tool in every system administrator's toolbox.
为各使用火灾报警系统的单位测试火灾探测器报警功能及安装施工工程单位安装验收过程中必备之工具。
For the use of fire alarm system, fire detector alarm unit testing and installation of construction engineering units during the installation and acceptance of the tools is necessary.
CAD系统作为相关设计部门的必备工具，发挥着越来越重要的作用。
CAD system has been a necessary tool and become more and more important in correlativity design departments.
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