In the years since the city of London imposed strict air-pollution regulations on local industry, the number of bird species seen in and around London has increased dramatically. Similar air-pollution rules should be imposed in other major cities.

Each of the following is an assumption made in the argument above EXCEPT:

(A) In most major cities, air-pollution problems are caused almost entirely by local industry.

(B) Air-pollution regulations on industry have a significant impact on the quality of the air.

(C) The air-pollution problems of other major cities are basically similar to those once suffered by London.

(D) An increase in the number of bird species in and around a city is desirable.

(E) The increased sightings of bird species in and around London reflect an actual increase in the number of species in the area.

看了以前的帖子，发现没有讨论B的。

我觉得B中，air quality是一个无关的概念。空气质量和鸟类回归在文中没有关联？

比如，某种物质对只有鸟类很敏感，该物质多了并不造成空气污染。否定了B，结论依然成立！为什么还说是结论？

引大牛的言论：

答案为A。almost entirely 太STRONG。air-pollution problems 太泛。对空气污染限制什麽，限制多少原文是不清楚的，所以不必有假设说污染几乎都是本地工业引起的。比如说对鸟伤害最厉害的是某种物质，就说SO2（二氧化硫），L是限制了它的排放使鸟数量增加，但二氧化硫却不是空气污染（air-pollution problems ）的主要原因。在这种情况下，否定了A，结论一样能成立。