ACT科学Session3地球学（Practice实战练习）

　　Practice 4

　　(52C-Passage I)

　　一位地质学家进行了三项研究， 从而评估水进入和离开湖泊的速度，以及其对湖泊水容量的影响。 水进入湖泊称为进水，而水离开湖泊称为出水。 这些研究历时五年。

　　Study 1

　　这位地质学家测量了进水的两个主要来源：降雨和湖水流入。这位地质学家用了五年的时间定期地对每个进水的来源进行了测量。通过这些测量，他计算了每年的平均降水总量为260×106立方米。图1展示了他的测量结果。

　　Study 2

　　水离开湖泊的方式主要是通过湖水流出、蒸发和深入到湖底的岩石之中。这位地质学家用了五年的时间定期地对这三种过程进行了测量。此外，一家水务公司用水泵将水从湖中抽出，以供附近的几个小区使用。 在研究期间，这家水务公司向地质学家给出了水泵的抽水速度。计算后的总出水量为300×106立方米/每年。 每个过程的平均出水量见表2。

　　Table 2

　　Study 3

　　这位地质学家在湖中央安装了一台水深度记录仪，并在这五年中每月定期读取测试数值。 每年，他算出这些数值的平均数，得出湖面每年平均降低10厘米。

　　Practice 4.1

　　If dams were constructed to effectively stop the escape of water by outflowing streams, which of the following is most likely?

　　A. Total outflow would equal total inflow.

　　B. Total outflow and lake volume would both probably increase.

　　C. Total outflow and lake volume would both probably decrease.

　　D. Total outflow would decrease and lake volume would increase.

　　Practice 4.2

　　If the area had experienced a lack of rainfall during the five-year study period, how would this have affected the results?

　　F. Total outflow would be higher.

　　G. Total inflow would be lower.

　　H. Infiltration would be higher.

　　J. All results would be unaffected by the drought.

　　Practice 4.3

　　Which of the following generalizations about the lake's water balance can be made based on the results of the studies?

　　A. For any lake, total water outflow always exceeds total water inflow.

　　B. The number of inflowing streams exceeds the number of outflowing streams.

　　C. If the rates of water entering and leaving a lake are not balanced, lake depth will change.

　　D. A lake cannot have both inflowing and outflowing streams and maintain a constant volume.

　　Practice 4.4

　　Would the geologist have obtained more accurate results if the investigation period was decreased from five to two years?

　　F. Yes, because there would be less chance of human error in the measurements.

　　G. Yes, because there would be fewer variables to consider.

　　H. No, because abnormally high or low measurements would distort the averages.

　　J. No, because water movement in and out of the lake is slow.

　　Practice 4.5

　　Which of the following assumptions was made in all three studies?

　　A. The three studies were done at different five-year periods.

　　B. The lake is underlain by rock that water cannot infiltrate.

　　C. Total inflow and outflow were constant during the investigation.

　　D. All significant inflows and outflows of water were identified.

　　Practice 4.6

　　Based on the results of the studies, the geologist concludes that lake volume decreased annually. Which of the following would help support that conclusion?

　　F. Determining if rainfall rate increased annually.

　　G. Determining if the surface area of the lake decreased annually.

　　H. Repeating the same studies on a different lake.

　　J. Repeating the depth measurements on a different lake.

　　Answers for Practice 4-6: Practice 4 D G C H D G

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