求助PREP2--CR1--98

Alpheaus

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.

Alpheaus

分析：
文中结论：防止漏油技术是有效的（客观事实），因此，对污染和鱼数量的减少的恐惧是无根据的。

问：前提假设

A：貌似说得太远了
B：是对文中已给事实的重复----防止漏油的技术是有效
C：引入新的元素，沉积在湖底的早期污染物也可导致再次污染
D：明确防油技术和对鱼数量造成伤害
E：描述和之前情况相同，如果释放及减少污染的情况也相同，湖水还是可以变清。但这次情况不同


整个读下来逻辑很混乱，觉得选项都可以选，比如D。。。求NN帮助！！

Alpheaus

假设题：

1 否定句取非-----是否削弱原文章

2否定句不是答案时，必为前后桥梁，补出文中的推理GAP

按照这种做法C是对的。但觉得ABDE都多少有些感觉。