新gre考试阅读机经：长江水稻
背景介绍： 在南亚发现了domesticated Rice,然后推测南亚是Rice的发源地，然后1985年在中国的长江流域发现了很多 wilder rice的遗址，推测生活在中国的先民有可能更早的驯化了rice。
提出旧理论： rice-farming最早在长江以南出现中 华 考 试 网
提出新理论： 认为长江流域的rice-farming可以往前推几百年。最后一段讲，1940年(?)调查的wild-rice其实主要确实是分布在南方，但是长江流域也有1、2种，所以还是有可能farming在北方也开始很早滴。然后我觉得这篇文章需要把握的就是wilder rice和 domesticated rice。搞清楚谁是野生的，谁是驯化的就可以了。
题目： 三个题考得都是逻辑相关，比如加强消弱什么的。
题目1： 最能undermine长江流域水稻是水稻祖宗的?
题目3： 作者是怎样利用geological graph还是什么graph来证明它的观点的。应该是从文章最后一段找，但我感觉文中没有直说，要自己推理。选项里好几个都很接近。
Since the 1970s, archaeological sites in China's Yangtze River region have yielded evidence of sophisticated rice-farming societies that predate signs of rice cultivation elsewhere in East Asia by a thousand years. Before this evidence was discovered, it had generally been assumed that rice farming began farther to the south. This scenario was based both on the geographic range of wild or free-living rice, which was not thought to extend as far north as the Yangtze, and on archaeological records of very early domestic rice from Southeast Asia and India (now known to be not so old as first reported). Proponents of the southern-origin theory point out that early rice-farming societies along the Yangtze were already highly developed and that evidence for the first stage of rice cultivation is missing. They argue that the first hunter-gatherers to develop rice agriculture must have done so in this southern zone, within the apparent present-day geographic range of wild rice.
Yet while most stands of wild rice reported in a 1984 survey were concentrated to the south of the Yangtze drainage, two northern outlier populations were also discovered in provinces along the middle and lower Yangtze, evidence that the Yangtze wetlands may fall within both the present-day and the historical geographic ranges of rice's wild ancestor
1. Which of the following, if true, would most clearly undermine the conclusion that the author makes based on the 1984 survey?
Areas south of the Yangtze basin currently have less wild-rice habitat than they once did.
Surveys since 1984 have shown wild rice populations along the upper Yangtze as well as along the middle and lower Yangtze.
The populations of wild rice along the Yangtze represent strains of wild rice that migrated to the north relatively recently.
Early rice-farming societies along the Yangtze were not as highly developed as archaeologists once thought.
In East Asia, the historical geographic range of wild rice was more extensive than the present-day geographic range is.