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题库 / OG2016-RC-109
There are recent reports of apparently drastic declines in amphibian populations and of extinctions of a number of the world's endangered amphibian species. These declines, if real, may be signs of a general trend toward extinction, and many environmentalists have claimed that immediate environmental action is necessary to remedy this "amphibian crisis," which, in their view, is an indicator of general and catastrophic environmental degradation due to human activity.
To evaluate these claims, it is useful to make a preliminary distinction that is far too often ignored. A declining population should not be confused with an endangered one. An endangered population is always rare, almost always small, and, by definition, under constant threat of extinction even without a proximate cause in human activities. Its disappearance, however unfortunate, should come as no great surprise. Moreover, chance events—which may indicate nothing about the direction of trends in population size—may lead to its extinction. The probability of extinction due to such random factors depends on the population size and is independent of the prevailing direction of change in that size.
For biologists, population declines are potentially more worrisome than extinctions. Persistent declines, especially in large populations, indicate a changed ecological context. Even here, distinctions must again be made among declines that are only apparent (in the sense that they are part of habitual cycles or of normal fluctuations), declines that take a population to some lower but still acceptable level, and those that threaten extinction (e.g., by taking the number of individuals below the minimum viable population). Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past.
It is indisputably true that there is simply not enough long-term scientific data on amphibian populations to enable researchers to identify real declines in amphibian populations. Many fairly common amphibian species declared all but extinct after severe declines in the 1950s and 1960s have subsequently recovered, and so might the apparently declining populations that have generated the current appearance of an amphibian crisis. Unfortunately, longterm data will not soon be forthcoming, and postponing environmental action while we wait for it may doom species and whole ecosystems to extinction.
It can be inferred from the passage that the author believes which of the following to be true of the amphibian extinctions that have recently been reported?
They have resulted primarily from human activities causing environmental degradation.
They could probably have been prevented if timely action had been taken to protect the habitats of amphibian species.
They should not come as a surprise, because amphibian populations generally have been declining for a number of years.
They have probably been caused by a combination of chance events.
They do not clearly constitute evidence of general environmental degradation.
题目分析：
文章推断题：可以推断，关于最近的两栖动物灭绝，作者相信？
选项分析：
A选项：灭绝是人类活动（造成环境恶化的人类活动）导致的：文章第二段开始都在质疑这个观点。
B选项：灭绝是可以被预防的，如果及时采取行动保护两栖动物的栖息地：文章没有提保护栖息地会不会预防灭绝。
C选项：灭绝并不令人意外，因为两栖动物数量已经下降很多年了：文章提到数量近几年在波动，并没有一直下降。
D选项：灭绝是由多个偶发事件（chance event）导致的：并没有明确的数据说明灭绝是偶发事件导致的。
E选项：正确。他们没有清晰的组成“环境恶化”的证据：正确。作者认为数量下降并不一定标志着环境恶化，也有其他原因和影响。
D答案最错在于作者从来没有说过近期出现population decline的那个动物会灭绝，所以也就不存在讨论灭绝的原因是什么。
C选项：They should not come as a surprise, because amphibian populations generally have been 【declining】 for [a number of years].灭绝并不令人意外，因为两栖动物数量已经下降很多年了：文章提到some amphibian populations have shown strong 【fluctuations】 [in the past].数量近几年在【波动】，并没有一直下降。
D选项：灭绝是由多个偶发事件（chance event）导致的： chance event只是灭绝的一种可能性原因，原文没有直接说【两栖动物的灭绝】就是有可能是因为chance event导致的
E选项：正确。他们没有清晰的组成“环境恶化”的证据：正确。作者认为数量下降并不一定标志着环境恶化，也有其他原因和影响。（显然在文中直接提到，比起D选项更合理）
D. chance event只是灭绝的一种可能性原因，并且是建立在数量小的基础上的，原文没有直接说两栖动物的灭绝就是有可能是因为chance event导致的
E. 显然在文中直接提到，比起D选项更合理
定位： Moreover, chance events—which may indicate nothing about the direction of trends in population size—may lead to its extinction.
C项 some amphibian populations have shown strong fluctuations in the past. 并不是下降很多年
probably和may lead to its extinction不可以互换吗？？？无语了。
rc
a错，看清楚文中"amphibian crisis," which, in their view, is an indicator of general 是他们的观点，不是author的观点！“ the author believes ”
错选d，作者说的是“the amphibian extinctions”，而d是在说An endangered population。而且跟文中说法词汇太相似的基本都是错的chance events，一定要经过变形，不要脑子一热就去选
constitute 构成
e对，第一段以后一直在讲的就是the amphibian extinctions 并不 clearly constitute evidence of general environmental degradation.
只有第一段最后一句提了一下而已。可是后面文章的反驳都没有提到了，这也算？那我就觉得D那个combination可以接受诶。
文章是在讲环境恶化吗？文章不是在讲amphibian的数量下降和灭绝吗？什么鬼啊。。。
d 嗯。。have been caused 说明已经造成了，但原文只说may 可能有影响。 e 因为整篇文章中心是讨论环境学家的写个claim ，第二段分析导致灭绝的因素，没有说到claim中的environmental degradation 所以okay.
Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past
The author states that chance events can lead to extinction. However, the author does not speculate on whether this is true in the case of the amphibians. It most likely is not, since the author claims that chance events can lead to extinction specifically in the case of endangered species, and does not state that the amphibians were previously endangered.
实际上整篇文章就是在question第一段那些environmentalist得出的结论，就是E选项。
直觉
They do not clearly constitute evidence of general environmental degradation. 对
第二段最后一句Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past.
They have probably been caused by a combination of chance events. 错 ，作者没这么说
combination of chance events
我想了很久，d的问题可能是出在了combination上面。
以及这个文章我觉得大意是，目前报告说了两件事一是两栖动物数量下降，二是濒危的两栖动物大量灭绝，科学家遂认为，危机来了
于是第二段解释了它们灭绝有哪些那些原因——灭绝和危机没啥关系
第三段解释了，他们数量下降有那些哪些原因——数量少和危机没啥关系。
此题求解释。。。。。
recently been reported?
have recently been reported?
Moreover, chance events—which may indicate nothing about the direction of trends in population size—may lead to its extinction.
2，3，4段都在评估amphibian灭绝的可能性，不一定是因为环境恶化，还有其他可能，因此A的灭绝不能成为环境恶化的证据
这道题考得很综合，因为既考到了定位也考到了主旨。
题目问的是推断作者最有可能同意哪一个选项，考点范围是关于几种A动物种类近期灭绝的事实。
A: 定位第一段最后一句。从全文主旨角度出发，recent distinction关键词出现在第一段；而第一段主旨是环境学家的观点，不是作者的观点。排除。
B: 关键词could have been。个人认为可定位最后一段。作者观点是没有足够证据支持物种灭绝是否由人类活动导致，但人类仍需要有所行动保护物种。但这选项跟题目范围无关。排除。
C: 关键词surprise，定位第二段，讨论的是理论上endangered物种最后灭绝不应该是surprise，与recent report范围无关。排除。
D: 关键词chance event，定位第二段。与C一样和recent report范围无关。排除。
E: 关键词clearly constitute，可联系最后一段主旨句（第一句话），回归作者关于环境学家的观点的看法。