Tpo24阅读分析(3)

○is similar to the length of time all other molecules remain in that lake

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以a given molecule of water做关键词定位至最后一句，说Residence time是平均值，一个分子在lake里的时间取决于它的route，有可能很快也有可能很慢，所以正确答案是C，或者多或者少。A和B原文没说；D说反，原文都说了一个具体的分子和residence time不一样，错

(3)

plete the summary by selecting the THREE answer choices that express the most important ideas in the passage.

Water enters, remains, and eventually leaves a lake in a variety of ways.

Answer Choices

○By measuring the water quantities at each of a lake's inputs and outputs, it can be determined whether water enters the lake mainly from surface or groundwater sources. (对应第三段前半部分，正确)

○Changes in lake level and volume are caused principally by the amount of evaporation of water into the atmosphere. (原文没说，不选)

○It is sometimes possible to decide whether a lake is surface water dominated or seepage dominated by simple observation at different seasons. (对应第三段后半部分，正确)

○The average period of time that molecules of water spend in a lake—the residence time—varies from lake to lake and overtime within a particular lake. (对应第五段首句，而且第六段也在说变化，正确)