Question

求翻译GMAT句子，不要机翻，谢谢。

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. 翻译一下，再帮忙分析一下结构。谢谢

整篇文章在这里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 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, long-term data will not soon be forthcoming, and postponing environmental action while we wait for it may doom specie and ecosystems to extinction.

Answer 1

这个句子有个一个很重要的短语“all but”,这里不是“除了”的意思，是“几乎”，在这里，all but = almost. 另一个重要知识点是 比较省略，后半段是类比前半段，因此省略掉了predicate(谓语以及谓语后面的成分)。现在我来解释句子：
In the 1950s and 1960s, many widespread amphibian species were said to be almost extincted. 在五六十年代的时候普遍存在的两栖种群极度削减几乎灭绝。这里“declared all but extinct after severe declines in the 1950s and 1960s”是v-ed修饰语，用来修饰主语“amphibian species”。
However, these amphibian species have come back over time. 这些经历过几乎灭绝的两栖种群后来又复活了。这是主句，主语是“amphibian species”，谓语是“have recovered”。
接下来就是后半段了：
And, it could be the same situation occured right now. 现在也可能是同样的情况，“so might the apparently declining populations”就是从句主语，明显下降的种群也是如此，他们可能会复活，什么样的种群呢？
The same situation is that what appears to decline and is about to go extinct now may come back later. 就是那些明显下降导致现在灭绝危机的两栖种群“the apparently declining populations that have generated the current appearance of an amphibian crisis”。
整个句子意思就是说，在五六十年代的时候那些普遍存在的两栖种群在经历极具下降以后几乎灭绝，然后这些两栖种群又逐渐回归大自然（也就是最终并没有灭绝）。所以，现在表现出递减的两栖种群所造成的这种灭绝危机的现象，也有可能跟那时候一样，以后数量都还会回归，不会灭绝（注意这里是假设，可能，不是一定会回来，所以是“so might”）。
这样解释的话就应该很清楚了，如果楼主还是觉得不懂，那就要好好去看看语法改错了，对于句子结构各个成分要好好理解。有什么问题再问我。

Answer 2

许多相当常见的两栖动物因为50年代至60年代数量严重下降而被宣告灭绝，但结果随后又恢复繁殖。所以表面的数量下降可能导致看上去的两栖动物危机。

Answer 3

许多相当于常见的两栖动物物种几乎宣告灭绝严重下降 在1950年代和1960年代随后恢复，所以可能显然declning的种群产生当前出现的两栖动物的危机