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Unformatted text preview: aquifer, the region’s climate keeps the rates of water addition very small. ○Although the aquifer has been adding water at the rate of only half a centimeter a year, it will eventually accumulate enough water of fill Lake Huron. ○Because of the region’s present climatic conditions, water is being added each year to the aquifer.
○Even when the region experiences unfortunate climatic conditions, the rates of addition of water continue to increase.
Paragraph 3: The first wells were drilled into the Ogallala during the drought years of the early 1930’s. The ensuing rapid expansion of irrigation agriculture, especially from the 1950’s onward, transformed the economy of the region. More than 100,000 wells now tap the Ogallala. Modern irrigation devices, each capable of spraying 4.5 million liters of water a day, have produced a landscape dominated by geometric patterns of circular green islands of crops. Ogallala water has enabled the High Plains region to supply significant amounts of the cotton, sorghum, 120
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wheat, and corn grown in the United States. In addition, 40 percent of American grainfed beef cattle are fattened here.
4. The word “ensuing” in the passage is closest in meaning to ○Continuing
5. In paragraph 3, why does the author provide the information that 40 percent of American cattle are fattened in the High Plains? ○To suggest that crop cultivation is not the most important part of the economy of the High Plains
○To indicate that not all economic activity in the High Plains is dependent on irrigation
○To provide another example of how water from the Ogallala has transformed the economy of the High Plains
○To contrast cattlefattening practices in the High Plains with those used in other region of the United States
Paragraph 4 在 This unprecedented development of a finite groundwater resource with an almost negligible natural recharge rate—that is, virtually no natural water source to replenish the water supply—has caused water tables in the region to fall drastically. In the 1930’s, wells encountered plentiful water at a depth of about 15 meters; currently, they must be dug to depths of 45 to 60 meters or more. In places, the water table is declining at a rate of a meter a year, necessitating the periodic deepening of wells and the use of evermorepowerful pumps. It is estimated that at current withdrawal rates, much of the aquifer will run dry within 40 years. The situation is most critical in Texas, where the climate is driest, the greatest amount of water is being pumped, and the aquifer contains the least water. It is projected that the remaining Ogallala water will, by the year 2030, support only 35 to 40 percent of the irrigated acreage in Texas that is supported in 1980.
6. The word “unprecedented in the passage is closest in meaning to ” ○Difficult to control
○Without any restriction
○Unlike anything in t...
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.
- Fall '13