passage 6 大象矮化
★★☆

先看題:
1. The primary purpose of the passage is to 主旨目的
2. According to the passage, which of the following statements about?body size?in mammals is true? 直接細(xì)節(jié)題,定位+同義改寫(xiě),典型的定位失效題
文章講解:
①During the Pleistocene epoch, several species of elephants isolated on islands underwent rapid dwarfing. ②This?phenomenon was?not necessarily confined to the Pleistocene, but may have occurred much earlier in the Southeastern Asian islands, although evidence is fragmentary. ③Several explanations are possible for this dwarfing. ④For example,?islands often have not been colonized by large predators or are too small to hold viable predator populations. ⑤Once free from predation pressure, large body size is of little advantage to herbivores. ⑥Additionally,?island habitats have limited food resources, a smaller body size and a need for fewer resources would thus be favored. ⑦Interestingly,?the island rule is reversed for small mammals such as rodents, for which gigantism is favored under insular conditions.
①現(xiàn)象引入
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②繼續(xù)描述現(xiàn)象,可以認(rèn)為是作者觀點(diǎn)
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③給出解釋
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④?+ ⑥???⑦
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⑤
1. The primary purpose of the passage is to
A.?question?the plausibility of one explanation sometimes offered for the dwarfing of certain species living on islands 相反
B. argue that dwarfing of certain species living on islands occurred prior to the Pleistocene?無(wú)關(guān),來(lái)自于②句的以偏概全。
C. cite evidence suggesting that dwarfing may have?adverse consequences?for some species living on islands?沒(méi)有證據(jù),解釋現(xiàn)象,是找因不是找果,也可以認(rèn)為是相反
D. present some possible explanations for the dwarfing of certain species living on islands?符合
E. contrast the effects of insular conditions on species with large body size and species with small body?無(wú)關(guān)/相反,現(xiàn)象解釋,不是說(shuō)明文
?
2. According to the passage, which of the following statements about?body size?in mammals is true? 直接細(xì)節(jié)題,定位+同義改寫(xiě),典型的定位失效題
A. A large body is unfavorable to mammalian?[劍1]?species’ survival under?most conditions.?沒(méi)有證據(jù)
B. A large body tends to benefit small mammals living on islands.?符合
C. For most herbivorous mammals, a large body size is?easier?to sustain?[劍2]?in the absence of large predators.?相反,對(duì)應(yīng)⑤
D. Under most conditions, a small body is less beneficial to herbivorous mammals than to?nonherbivorous?mammals.?沒(méi)有證據(jù)
E. Among?nonherbivorous?mammals, a small body is more beneficial on anisland than on a mainland.?沒(méi)有證據(jù)
?[劍1]?[m??me?l??n]
?[劍2]保持,維持