Early in the twentieth century, Lake Konfa became very polluted. Recently fish populations have recovered as release of industrial pollutants has declined and the lake's waters have become cleaner. Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again. However, a technology for preventing leaks is being installed. Therefore, provided this technology is effective, the fears are groundless.

Which of the following, if true, most seriously weakens the argument?


The pipeline's construction will disturb sediments at the bottom of the lake, dispersing into the water toxic pollutants that have settled there.

Changes in land use and drainage patterns around the lake mean that the lake's waters are increasingly likely to be affected by agricultural runoff.

The leak-preventing technology has been in use for several years without any pipeline in which it is installed developing serious leaks.

A major leak of oil from the pipeline would harm not only the lake's fish but also populations of other aquatic animals and plants.

Since the beginning of the twentieth century, non-native species of fish have been introduced into the lake and now make up a considerable proportion of its overall fish population.

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情景：Konfa曾经被污染的很严重，现在被治理的很好。但是，最近政府打算在Konfa湖的湖底安装一条输油管道。有些人担心安装输油管道可能会导致湖水再次被污染。因此，只要有一个防止漏油的技术有效，那么这些担心就是多余的。

推理：

前提：一个防止漏油的技术可以让油管不漏
结论：不用担心安装输油管道可能会导致湖水再次被污染

答案预估：

那些“湖水不会被再次污染”的其它必要条件（常理上能保真推理出的一切结果）不存在。

选项分析：

A选项：Correct. 输油管的建立可能会扬起陈在湖底的沉淀物，重新扩散污染物。湖水要想不污染，必须断绝一切污染源。本选项给出了除了漏油会污染外，还有别的原因可能导致污染，可以削弱。

B选项：在Lake Konfa周围用土地和排污模式的变化会导致该湖会受到农业更严重的影响。本选项没有提及结论的其它必要条件。

C选项： 输油管的防漏技术从来没带来过严重的漏油事件。本选项没有提及结论的其它必要条件。

D选项：严重的漏油不仅仅会影响湖中的鱼，而且还会影响许多其他的水生动植物。本选项没有提及结论的其它必要条件。

E选项：从20世纪开始，有很多外来的鱼被引入到了湖水中并且占据了不小的比例。本选项没有提及结论的其它必要条件。

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Prep2008E1-CR
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