问题

［A］ New plants and animals then move i

［A］ New plants and animals then move into the area and begin to grow.

A［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.
B［C］ On a smaller scale, large mammals, such as elephants, regularly destroy rain forest vegetation in the Congo River Basin in Africa.
C［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.
D［E］ Less than one percent of the trees in the forest reside in the canopy and emergent layers.
E［F］ Because more light penetrates the canopy, however, the vegetation of the understory and forest floor is better developed than in the tropics.
F［G］ The rich, green canopy is teeming with life, and forest researchers have developed ingenious methods for accessing this mysterious ecosystem.

参考答案

参考解析：

本题考查的知识点是：段落内一致性原则+上下文的衔接本题空格出现在第一段中。上文提到热带雨林结构中的最低层是下层植被。下文提到，下层植被的植物叶子呈深红色，从而能够获取到达下层植被的少量的光。由此可见，上下文都围绕“下层植被”展开论述。出现关键词“understory”的选项有［B］、［D］和［F］。但是，［D］出现了上下文没有的新信息：“藤蔓植物”。［F］中出现了“冠层（canopy）”，但从下文即第一段倒数第二句对canopy一词的定义可知，它应在下文中第一次出现。由此排除［D］和［F］项。［B］强调下层植被适应低光强的特性，其中“低光强”与下文“获取少量的光”、“吸收不同波长的光”等内容相呼应。

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