这种环境是由开发团队管理的；它是供开发人员日常使用的并且可以在必要时进行升级以执行他们的测试。
This environment is controlled by the development team; it is used informally by developers and updated as often as necessary by developers while performing their tests.
模型以需要理解此模型的一组用户为目标受众，相同的系统可以表示为完全不同的模型，供不同的人员使用。
Models are targeted to a group of users that will understand them, and the same system can be represented by distinct models so that it is understood by a variety of people.
工作人员经常检查水龙头，以确保有足够的水龙头供难民们使用。
Regular checks ensure that sufficient number of taps are functional for use by people living in the camps.
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