一道费解题

毛哥二战要上720

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, those fears are groundless. The argument depends on assuming which of the following? A. Apart from development related to the pipeline, there will be no new industrial development around the lake that will create renewed pollution in its waters. B. There is no reason to believe that the leak-preventing technology would be ineffective when installed in the pipeline in Lake Konfa. C. The bottom of the lake does not contain toxic remnants of earlier pollution that will be stirred into the water by pipeline construction. D. Damage to the lake’s fish populations would be the only harm that a leak of oil from the pipeline would cause. E. The species of fish that are present in Lake Konfa now are the same as those that were in the lake before it was affected by pollution. B我明白是错的，为什么不选a啊。 a就是没有别的企业再有工程啊 谢谢大神们

荒草

A显然out of scope了
fears voice 说的是新oil pipeline的污染

毛哥二战要上720

荒草 发表于 2013-10-31 10:11
A显然out of scope了
fears voice 说的是新oil pipeline的污染

可是C我还是不太明白，这底下的残留物怎么会通过管道进入水源了呢。不科学啊

荒草

fears voice担心的是管道造成污染
作者argu说管道不会leak, 因此不用担心, 他排除了一个原因, 那其他原因呢? 所以assumption的方向应该是没有其他和这个管道相关的因素会造成污染.
那C选项, 在没有残留物, 所以安装过程中污染不会被搅和上来. 等于是加强了作者的推理. 于是两个因素一起推出, fears 可以放心