Methods General investigation was adopted to understand the water supply situation in rural areas and stratified random sampling was used to monitor the water quality.

方法按照相关调查表要求，对农村供水情况进行普查，供水水质采用分层随机抽样的方法进行监测。

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It explains in detail how concrete changes into clean water concrete and mirror surface concrete in the construction process, and solves the general quality problem of concrete.

文中详细介绍了混凝土在施工过程中如何成为清水混凝土和镜面混凝土，解决了混凝土的质量通病。

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In general, the frequency of cleaning necessary, will depend on the quality of water used in the device as well as the quality of air used in the device and is present in the laboratory.

通常情况下，清洗所需频率取决于该装置所使用的水和空气的质量，在本实验室已有介绍。

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