Some archaeologists speculate that the Americas might have been initially colonized between 40,000 and 25,000 years ago. However, to support this theory it is necessary to explain the absence of generally accepted habitation sites for that time interval in what is now the United States. Australia, which has a smaller land area than the United States, has many such sites, supporting the generally accepted claim that the continent was colonized by humans at least 40,000 years ago. Australia is less densely populated (resulting in lower chances of discovering sites) and with its overall greater aridity would have presented conditions less favorable for hunter-gatherer occupation. Proportionally, at least as much land area has been lost from the coastal regions of Australia because of postglacial sea-level rise as in the United States, so any coastal archaeological record in Australia should have been depleted about as much as a coastal record in the United States. Since there are so many resource-rich rivers leading inland from the United States coastlines, it seems implausible that a growing population of humans would have confined itself to coasts for thousands of years. If inhabitants were present 25,000 years ago, the chances of their appearing in the archaeological record would seem to be greater than for Australia.The passage is primarily concerned with doing which of the following?A. Presenting an objection to a claimB. Accounting for an apparent anomalyC. Outlining an alternative interpretationD. Correcting a particular misconceptionE. Questioning the validity of a comparison答案:A在这篇文章中,一开始指出考古学家认为如今的美国地区最初被人类所居住是在4万到2万5千年前。但是,作者说,考古学家需要解释为什么找不到那个时期人类居住的痕迹。接着,一系列细节让作者得出了一个判断,即假如考古学家的观点为真的话,他们理应能够找到考古遗迹才对。 所有这些信息指向一个最终的目的,即考古学家的观点是不靠谱的。然而,这个观点从头到尾作者都没有直接说出,而需要由我们自己从文章信息中推断出来。其论证过程是由前提(考古学家观点若为真 → 能找到遗址),加前提(没找到遗址),推断出结论(考古学家观点不为真),符合逻辑学基本定理modus tollens,即前提(p → q)加前提~q可以推出结论~p。 我们都希望一篇否定他人观点的文章以如下明确的方式表达态度,比如“某人认为XXX是对的。但是,很显然,他的观点没有道理的。”可是,在GRE偏难的文章中,我们很难期待作者把话说得这么直接,而题目恰恰就会考察我们能否把文章隐藏的目的推敲出来的能力。 显然,如同先前几条能力所要求,GRE考试对文章的主旨考察也需要我们主动的介入文本,而不是被动的接受文章的字面意思。“名师介绍:万炜,北京大学新闻学学士、哲学硕士 ,哲学系的背景使得分析性写作课程逻辑性极强,尤其是在Syracuse大学教授逻辑课程的经历,使其教授的语言的应用性与灵活性很高。课堂上不仅致力于提升学生的语言水平本身,同时也教会学生灵活的利用自己现有的语言能力,将难以表达的思想用恰当的方式表达出来。地道的美式口音加之其美式幽默深受学生欢迎。完整内容请戳【阅读原文】