托福阅读推理题中那些“逆向推理”.docx

托福阅读推理题中那些“逆向推理”托福阅读推理题每篇0-2道，考查学生理解和感知文章内容关系的能力，需要学生根据句子之间的逻辑性进行更深层次的推断。有时候，我们可以利用“正向推理”：找出与文章描述特质一致的选项。也有一些题，文章给我们的提示其实正是题干概念相反范畴的特质，这需要我们以此出发，逆推出题干范畴的特质，再得出答案。那么，托福阅读推理题中会有哪些情况涉及“逆向推理”呢?第一种情况：新的时间点引发的逆向推理例题一：来自-Petroleum Resources-第6题Paragraph 3: Oil pools are valuable underground accumulations of oil, and oil fields are regions underlain by one or more oil pools. When an oil pool or field has been discovered, wells are drilled into the ground. Permanent towers, called derricks, used to be built to handle the long sections of drilling pipe. Now portable drilling machines are set up and are then dismantled and removed. When the well reaches a pool, oil usually rises up the well because of its density difference with water beneath it or because of the pressure of expanding gas trapped above it. Although this rise of oil is almost always carefully controlled today, spouts of oil, or gushers, were common in the past. Gas pressure gradually dies out, and oil is pumped from the well. Water or steam may be pumped down adjacent wells to help push the oil out. At a refinery, the crude oil from underground is separated into natural gas, gasoline, kerosene, and various oils. Petrochemicals such as dyes, fertilizer, and plastic are also manufactured from the petroleum.6.Which of the following can be inferred from paragraph 3 about gushers?They make bringing the oil to the surface easier.They signal the presence of huge oil reserves.They waste more oil than they collect.They are unlikely to occur nowadays.题目解析：选D. 在第三段中的第六句uAlthough this rise of oil is almost always carefully controlled today, spouts of oil, or gushers, were common in the past.(虽然今天油上升到地表的过程被小心地控制着，但在过去自喷井是很常见的。)”， “today”时间点的出现提醒我们现在和过去的不同。因此D选项正确。这里文章中提到的特质“were common”是关于gushers在in the past的表现，而选项中的是说nowadays，逆推得到的选项。第二种情况：新的地点引发的逆向推理例题二：来自-The Geologic History of the Mediterranean-第4题Paragraph 3: With question such as these clearly before them, the scientists aboard the Glomar Challenger processed to the Mediterranean to search for the answers. On August 23, 1970, they recovered a sample. The sample consisted of pebbles of hardened sediment that had once been soft, deep-sea mud, as well as granules of gypsum and fragments of volcanic rock. Not a single pebble was found that might have indicated that the pebbles came from the nearby continent. In the days following, samples of solid gypsum were repeatedly brought on deck as drilling operations penetrated the seafloor. Furthermore, the gypsum was found to possess peculiarities of composition and structure that suggested it had formed on desert flats. Sediment above and below the gypsum layer contained tiny marine fossils, indicating open-ocean conditions. As they drilled into the central and deepest part of the Mediterranean basin, the scientists took solid, shiny, crystalline salt from the core barrel. Interbedded with the salt were thin layers of what appeared to be windblown silt.4.Which of the following can be inferred from paragraph 3 about the solid gypsum layer?It did not contain any marine fossil.It had formed in open-ocean conditions.It had once been soft, deep-sea mud.It contained sediment from nearby deserts.题目解析：选A.根据本段倒数第三句“Sediment above and below the gypsum layer contained tiny marine fossils.(石膏层之上和之下的部分包含微小的海洋生物化石。)”可以推断出石膏层不包含这样的化石。本题就是从文章中关于其他地点：“之上和之下”的特质推断出题干概念范畴特质的例子。第三种情况：特定词引发的逆向推理像是“unlike”“without”等词可以作为我们进行逆向推理的依据。例题三:来自- The Origins of Cetaceans-第2题Paragraph 1: It should be obvious that cetaceanswhales, porpoises, and dolphinsare mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.2. Which of the following can be inferred from paragraph 1 about early sea otters?It is not difficult to imagine what they looked like.There were great numbers of them.They lived in the sea only.They did not leave many fossil remains.题目解析：选A.定位到第4句“However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is n