对已有水文资料的流量测验次数选择进行允许误差分析，是水文站开展水文巡测的前期性工作。

The analysis of tolerated error in the selection of times for flow tests in hydrologic data available is the initial stage work for a hydrologic station to launch hydrologic surveys.

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昨天，我们班进行了一次数学测验。

Yesterday, we had a math class test.

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医生给人们做了一次数学测验。

The doctor gave people a maths test.

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