考研英语

阅读原文段：

As Gilbert White，Darwin， and others observed long ago， all species appear to have the innate capacity to increase their numbers from generation to generation. The task for ecologists is to untangle the environmental and biological factors that hold this intrinsic capacity for population growth in check over the long run. The great variety of dynamic behaviors exhibited by different population makes this task more difficult： some populations remain roughly constant from year to year others exhibit regular cycles of abundance and scarcity still others vary wildly， with outbreaks and crashes that are in some cases plainly correlated with the weather， and in other cases not.

3.According to the text， all of the following behaviors have been exhibited by different populations EXCEPT

[A] roughly constant population levels from year to year.

[B] regular cycles of increases and decreases in numbers.

[C] erratic increases in numbers correlated with the weather.

[D] unchecked increases in numbers over many generations.

「答案」D

「考点解析」这是一道审题定位与中心主旨题。根据本题题干中的“different populations”可将本题的答案信息来源确定在首段的句，因为该句中的“all species”实际上指的就是题干中的“different populations”。从段的首句入手并且仔细阅读首段的第二句，就可以找出本题的正确选项D，因为该选项所传达的信息与原文段、二句所传达的信息不一致。考生在解题时一定要学会迅速审题定位的能力。的内容，就可以找出本题的正确选项B.考生在解题时一定要正确理解原文所传达的含义，即进行正确的细节推导。