GMAT真题训练1：

　　Which of the followingmost logically completes the argument below?

　　Davison River farmers arecurrently deciding between planting winter wheat this fall or spring wheat nextspring. Winter wheat and spring wheat are usually about equally profitable.Because of new government restrictions on the use of Davison River water forirrigation, per acre yields for winter wheat, though not for spring wheat,would be much lower than average. Therefore, planting spring wheat will be moreprofitable than planting winter wheat, since .

　　(A) the smaller-than-average size of a winterwheat harvest this year would not be compensated for by higher winter wheatprices

　　(B) new crops of springwheat must be planted earlier than the time at which standing crops of winterwheat are ready to be harvested

　　(C) the spring wheat thatfarmers in the Davison River region plant is well adapted to the soil of theregion

　　(D) spring wheat has usesthat are different from those of winter wheat

　　(E) planting spring wheatis more profitable than planting certain othercrops, such as rye

　　分析：

　　原文：政府对灌溉用水的限制--冬小麦每英亩产量减小---冬小麦和春小麦的选择

　　问题：春小麦利润高的理由。

　　解题关键：原文谈钱，选项谈钱更有关。

　　选项：

　　A，冬小麦高价不能补偿冬小麦收获的减少;潜台词：冬小麦利润减少，小于春小麦。有关

　　B，春小麦的种植必须早于冬小麦的收割;种植时间，无关。

　　C，春小麦更适合土壤;无关。

　　D，春小麦的作用与冬小麦不同，无关。

　　E，种春小麦比其他庄稼利润高。无关比较。

　　答案：A

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　　GMAT真题训练2：

　　When there is lessrainfall than normal, the water level of Australian rivers falls and the riversflow more slowly. Because algae whose habitatis river water grow best in slow-moving water, the amount of algae per unit of watergenerally increases when there has been little rain. By contrast, however,following a period of extreme drought, algae levels are low even in veryslow-moving river water.

　　Which of the following, if true, does most toexplain the contrast described above?

　　(A) During periods ofextreme drought, the populations of some of the species that feed on algae tendto fall.

　　(B) The more slowly watermoves, the more conducive its temperature is to the growth of algae.

　　(C) When algaepopulations reach very high levels, conditions within the river can becometoxic for some of the other species that normally live there.

　　(D) Australian rivers dryup completely for short intervals in periods of extreme drought.

　　(E) Except during periodsof extreme drought, algae levels tend to be higher in rivers in which the flow has been controlled by damming than in rivers that flow freely.

　　原文：(雨量减少、流速较低、)严重干旱---algae生长

　　问题：解释对比关系

　　解题关键：

　　选项：

　　A，干旱时，一些以algae为食的物种减少; 无意义概率，反向;

　　B，水流越慢，温度越适宜;无关;

　　C，algae 数量较高时，环境变得对其他物种有毒;无关

　　D，极度干旱时河水短期枯竭;潜台词，无法生长，有关

　　E，除了干旱期，algae水平在水流受大坝控制的河里比在自由流动的河里较高;无关比较。

　　答案：选D