13年版GMAT官方指南阅读解析-智课教育.pdfVIP

智 课 网 G M A T 备 考 资 料 13年版GMAT官方指南阅读解析-智课教育 13年版GMAT官方指南阅读解析，12年版官方指南的文章数目为2 4篇，而13年版官方指南的文章数目为26篇，但题目数量仍然是139道 。13年版官方指南中主旨题的比例由原来的15.1%变为现在的15.8%， 而逻辑题的比例保持3%不变。 新文章共7篇，其中2长5短，2篇商科类文章，2篇社会科学类文章 ，2篇生物学文章，1篇天体物理学文章。 新题共27道，题号是：1-4，11-17，37-41，52-55，84-86，11 1-114，其中主旨结构题7道，细节题20道。 样题分析 Biologists have advanced two theories to explain why schooling of fish occurs in so many fish species. Because schooling is particularly wide spread among species of small fish, both theories assume that schooling offers the advantage of some protection from predators. Proponents of theory A dispute the assumption that a school of thousands of fish is highly visible. Experiments have shown that any fish can be seen, even in very clear water, only within a sphere of 200 meters in diameter. When fish are in a compact group, the sphere of visibility overlap. Thus, the chance of a predator finding the school is only slightly greater than the chance of the predator finding a single fish swimming alone. Schooling is advantageous to the individual fish because a predators chance of finding any particular fish swimming in the school is much smaller than its chance of finding at least one of the same group of fish if the fish were dispersed throughout an area. However, critics of theory A point out that some fish form schools even in areas where predators are abundant and thus little possibility foexcaping detection exists. They argue that the school continues to be of value to its members even after detection. They advocate theory B, the confusion effect, which can be explained in two different ways. Sometimes, proponents argue, predators simply cannot decide which fish to attack. This indecision supposedly results from a predators preference for striking prey that is distinct from the rest of the school in appearance. In many schools the fish are almost indentical in