［A］ New plants and animals then move into the area and begin to grow.
［B］ Just 2 percent of the sunlight goes through the many layers of leaves and branches above, so understory plant species have developed special traits to cope with low light levels.
［C］ On a smaller scale, large mammals, such as elephants, regularly destroy rain forest vegetation in the Congo River Basin in Africa.
［D］ An understory of shorter trees and a lacework of woody vines, or lianas, produce a forest of such complex internal architecture that many animals, including some sizable ones, rarely or never descend to the ground.
［E］ Less than one percent of the trees in the forest reside in the canopy and emergent layers.
［F］ Because more light penetrates the canopy, however, the vegetation of the understory and forest floor is better developed than in the tropics.
［G］ The rich, green canopy is teeming with life, and forest researchers have developed ingenious methods for accessing this mysterious ecosystem.
正确答案：A
本题考查的知识点是：上下文的衔接
本题空格出现在第四段末上文介绍了雨林中连续的的树层可能遭到的破坏及影响下文即第五段首句提到其他的自然干扰会造成冠层更大的空隙由此可知上下文论述的是自然干扰对树层的影响根据段落一致原则空格处应延续上文的内容［A］和上文能够衔接其中thearea指代上文中theforestfloor［C］有一定的干扰性其中destroy一词与上文disturb呼应但是从内容看“非洲刚果河盆地的热带雨林植被”无法与上文“连续的树层”衔接［D］虽然重现了上文的词语vines但其内容与上下文毫无关联［F］干扰性最大其中从句“由于更多的阳光穿透森林冠层”与上文衔接非常紧密但是主句内容与上下文都无法衔接而且出现了新信息“inthetropics”
