标题: OG10-53,心里的疑惑望牛牛们指教 [打印本页] 作者: sasha_wen 时间: 2010-12-30 00:18 标题: OG10-53,心里的疑惑望牛牛们指教 Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle. Which of the following statements, if true, would most strengthen the scientists’ hypothesis? (A) The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees. (B) Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were critical breeding areas for the native species of fish. (C) The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas the lowest recorded temperature of the river after the dam was built has been 43 degrees. (D)Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing with the declining native fish species for food and space. (E) Five of the fish species native to the Emerald River are not native to any other river in North America.
文章的结构是：8种土产鱼繁殖不充分，因为河水温度变化范围减少即从原先周期50到6，科学家假定上升的温度提示繁殖，我认为科学家的假设就是温差的减少引起了繁殖的不充分，所以为了加强假设，就是要说明鱼只能在温差50里繁殖，这样直接点明现在温差减少，繁殖下降。 不知道我的分析是否正确，望牛牛们指导，拍砖！作者: sdcar2010 时间: 2010-12-30 00:28
A is the answer. Your understanding is right. But you'd better think in English when preparing for GMAT.作者: lonelyorchid 时间: 2011-1-2 14:37
分析是正确的