一个逻辑问题，大全TEST B的第二题，想不通答案……求牛人指导！

竹灵溪月

2. In the years sincethe city of London imposed strict air-pollutionregulations on local industry, the number of bird species seen in and around London
has increaseddramatically. Similar air-pollution rules should be imposed in other majorcities. Each of the followingis an assumption made in the argument above EXCEPT:
(A) Inmost major cities, air-pollution problems are caused almost entirely by localindustry.
(B) Air-pollutionregulations on industry have a significant impact on the quality of the air.
(C) The air-pollutionproblems of other major cities are basically similar to those once suffered by London
. (D) An increase in the number of bird species inand around a city is desirable.
(E) The increasedsightings of bird species in and around London
reflect an actual increase in the number of species in the area.

正确答案是A，我选了D，因为不明白鸟的种类很desirable为什么是一个assumption？？

竹灵溪月

哦~~也就是说这个假设是假设其他地区的人跟伦敦的市民一样，喜欢看到鸟类的增加，否则的话促进鸟类增加的措施就没有意义，是吧~？谢谢！！！无比感谢！！

bitieming

A之所以不是假设是因为用了极端词语，只要有相当部分的空气污染是当地企业产生的，该措施就会有效。
D是假设是因为原文说这种空气污染治理措施的作用是使鸟类数量增加，其中的假设是伦敦人喜欢看到更多的鸟类，所以对他们来说鸟类增加是好事。但是无法确定其他城市的人是不是也跟伦敦人一样渴望看到更多的鸟类，有可能很多城市讨厌鸟到处抛洒排泄物等等。