题目问的是是什么导致了这两个同类不同种的物种（不知道叫什么）在城市和乡下的数量差异。 A说的是这个物种吃虫子所以受到重视，简直答非所问。 B说的是这个物种会为了保护领地而攻击其他同类，文中根本没提到。 C说的文中更是没有提到。 E说其中一种是无性生殖，而且都是雌性，另一种是有性生殖，所以一个多一个少。也是莫名其妙，文中根本没说。 唯一跟虫子有关的就是D了。

这里选D没什么问题啊，就是因为在城市里面虫子多，所以根据题意，虫子多的地方这个什么house gecko才会displacing mourning gecko啊~森林里面虫子少，所以stable。

1. In rural areas ---> no lighted buildings ---> no gathering (congregation) of insects around lights ---> House gecko not stopping M gecko feeding on insects ---> probably no starving of M gecko ---> stable population In urban areas ---> lighted buildings ---> gathering (congregation) of insects around lights ---> House gecko stopping M gecko feeding on insects ---> probably starving of M gecko ---> reducing M gecko population after introduction of H gecko. I have just copied an answer from a website. http://www.beatthegmat.com/on-pacific-islands-a-newly-arrived-t82486.html 注册地在美国的网站。 2. A. In urban areas, geckos are valued because they eat so many insects. Gecko value and the reason for their value is irrelevant. B. Geckos defend territories against other members of the same species. This doesn't address urban areas or why one gecko species would have a greater population than the other. C. House geckos that arrive on islands are carried there in boats and planes. How the geckos arrive is not relevant. D. places where there are lighted buildings, insects tend to gather around the light. The house gecko prevents the mourning gecko from feeding in areas where insects congregate. Insects congregate around light. If the mourning gecko is prevented from feeding this would encourage its displacement. E. Mourning geckos are all females and reproduce asexually, but house geckos reproduce sexually. Differing methods of reproduction does not explain the difference in population. http://gmatclub.com/forum/on-pacific-islands-a-newly-arrived-gecko-species-the-house-42722.html 注册地在加拿大的网站。

From the article, it's the population density that impacts the two species. So when they are sparsely populated (in rural areas) there is no issue. However, in densely populated areas - presumably where there's more food - the competition for food impacts the population difference. Thus D is the closest because it indicates where there's lights...there's more food...then there's more geckos competing.

D项解释。 lighted buildings为灯火通明的建筑，这里包括城市urban areas和乡村rural areas 有人居住的地方。insects tend to gather around the light. -> 昆虫喜欢聚集在灯光周围。(科学上的发现也是如此，许多昆虫喜欢聚集在有光的地方，做题可以暂时忽略这点。) popluations of the two species are more stable in rural areas far from human settlement 这两个物种在rural areas 并且远离人类居住的地方数量保持stable. the house gecko does not attack the mourning gecko, house gecko不会攻击mourning gecko,（然后后面跟了个but，感觉这个句子为了出题故意去掉了一些修饰成分。） but in areas where insects congregate it prevents the mourning gecko from feeding on them. 但是在昆虫聚集的地区，昆虫(I think 'it' should be 'they')阻止/抵抗mourning gecko以他们为食(或者说mourning gecko无法捕食足够的昆虫)。所以此时house Gecko就应该会攻击mourning gecko了。 注意这个but。(其实这个but感觉转折的好奇怪，不知是不是出题的人故意的。) 总结就是：有昆虫大量聚集地地方，house gecko 就会攻击/取代mourning gecko(因为无法以昆虫为食物) ；而在远离人类居住地地方，house gecko不会攻击/取代mourning gecko，或者说能够共处。 因为在城市和靠近乡村(有人居住)的地方(lighted buildings)，house gecko取代了mourning gecko。说明这些地方昆虫很多，所以才会导致mourning gecko的灭亡或迁移。 或许这篇文章的意图就是想论证house gecko取代mourning gecko和昆虫(聚集与否)的关系。 逻辑论证不是非常的严谨。 ssy3141对其他选项的排除法很好。