Gemj的“逻辑大全”若干问题/大全-B-1,大全-B-2

v22

2. 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. 答案是A，我觉得应该是D啊。因为提干问的是assumption的问题，D中。。。increase。。。desirable在原文本来就有了“。。。。increased dramatically”，所以为什么不是D而是A呢？唉，逻辑一向是我的弱项，各位大虾请帮帮忙。如果谁觉得不值得问这些简单问题，可别见怪啊

why D cannot???/ 怎么会是A？哪位解释一下？