lz 8.1可能是这个 求验证 Plankton generally thrive in areas of the ocean with sufficient concentrations of certain nitrogen compounds near the surface, where plankton live. Nevertheless, some areas, though rich in these nitrogen compounds, have few plankton. These areas have particularly low concentrations of iron, and oceanographers hypothesize that this shortage of iron prevents plankton from thriving. However, an experimental release of iron compounds into one such area failed to produce a thriving plankton population, even though local iron concentrations increased immediately.
Which of the following, if true, argues most strongly against concluding, on the basis of the information above, that the oceanographers' hypothesis is false?
(A)Not all of the nitrogen compounds that are sometimes found in relatively high concentrations in the oceans are nutrients for plankton. (B)Certain areas of the ocean support an abundance of plankton despite having particularly low concentrations of iron. (C)The release of the iron compounds did not increase the supply of nitrogen compounds in the area. (D)A few days after the iron compounds were released, ocean currents displaced the iron-rich water from the surface. (E)The iron compounds released into the area occur naturally in areas of the ocean where plankton thrive. weaken 选D
谷物那道和OG的这个类似： 28. Gortland has long been narrowly self-sufficient in both grain and meat. However, as per capita income in Gortland has risen toward the world average, per capita consumption of meat has also risen toward the world average, and it takes several pounds of grain to produce one pound of meat. Therefore, since per capita income continues to rise, whereas domestic grain production will not increase, Gortland will soon have to import either grain or meat or both. Which of the following is an assumption on which the argument depends? (A) The total acreage devoted to grain production in Gortland will soon decrease. (B) Importing either grain or meat will not result in a significantly higher percentage of Gortlanders’ incomes being spent on food than is currently the case. (C) The per capita consumption of meat in Gortland is increasing at roughly the same rate across all income levels. (D) The per capita income of meat producers in Gortland is rising faster than the per capita income of grain producers. (E) People in Gortland who increase their consumption of meat will not radically decrease their consumption of grain.（答案E）
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2011-7-7 14:53:28
楼主
