2016年10月30日GRE阅读真题回忆

　　短文章：

　　For years, the leading theory for what caused the Younger Dryas (a dramatic reversal, about 12,900 years ago, in a global warming trend) was a release of water from Glacial Lake Agassiz. The theory posited that this meltwater flooded into the North Atlantic, lowering the salinity and intensity of surface waters enough to prevent them from sinking. Ocean currents were changed in such a way that northward transport of heat in the ocean diminished, and the North Atlantic regions plunged back into near-glacial conditions. However, evidence has emerged that the Younger Dryas began long before freshwater flooded the North Atlantic. Additionally, the temperature changes included by a shutdown in the North Atlantic heat conveyor system are too small to explain the Younger Dryas.

　　1.The author of the passage implies which of the following about the release of water from glacial Lake Agassiz?

　　A. The notion that the release occurred has been challenged by more recent findings.

　　B. The release probably occurred much earlier than scientists have generally assumed.

　　C. The release would not have been sufficient to cause any temperature change in the North Atlantic.

　　D. The timing of the release is such that it probably did not trigger the onset of the Younger Dryas.

　　E. The release was probably unrelated to the global warming trend that was taking place.

　　答案：选D.

　　解析：问下面哪个是作者暗示的和放水相关的.D说放水时机是这样的因此不可能带来YD的开始，完美符合选文中转折后面放水YD之后的描述。A选项质疑放水这件事的发生时原文没提及的。B说放水比科学家所普遍假设的要早，如果把科学家普遍假设和leading theory放在一个队伍的话，他们之前认为放水带来YD，那他们肯定认为放水要早咯，而实际YD要更早，那实际放水时间肯定比科学家假设的要晚。C选项错在any,太绝对了，没说放水一点温度变化也不能带来。E选项文章没说放水和全球变暖的关系。