单选题 Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Broil, two queens in the United States share a nest. Ants from these nests are more aggressive than those from single-queen nests. By destroying virtually all insects in the nest area, these aggressive ants gain sole access to food sources, and the ant population skyrockets. Since certain predator insects in Brazil limit the fire-ant population there, importing such predator insects into the United States would be of overall benefit to the environment by stopping the increase of the fire-ant population in the United States.
Each of the following is an assumption made in the argument EXCEPT:

A、 The imported insects would not prove more damaging to the environment in the United States than are the fire ants themselves.
B、 The predator insects from Brazil could survive in the ecological environment found in the United States.
C、 The especially aggressive fire ants from the two-queen nests would not be able to destroy the Brazilian predator insects.
D、 The predator insects would stop the increase of the ant population before the ants spread to states that are farther north.
E、 (E) The rate of increase of the fire-ant population would not exceed the rate at which the predator insects could kill the ants.

【正确答案】 D

【答案解析】[解析] 本题不好直接找答案，因此最好用排除法。由本题的论述可以推知要想使从巴西引进的昆虫能对美国南部地区的环境有益，首先得保证这种昆虫在该地区能够存活，其次是这种昆虫给这个地区的环境带来的益处要大于害处；要想使这种昆虫抑制住火蚁数量的增加，首先就要求是这种昆虫吃掉了火蚁，而不是火蚁吃掉了这种昆虫，其次要求这种昆虫杀死火蚁的比率要超过火蚁数量增加的比率。根据此分析可知(A)、(B)、(C)、(E)选项都是上题论述依赖的假设；(D)选项的“the ant population”为模糊概念，可能包括“fire ants”，也可能没包括“fire ants”，所以(D)为无关选项，因此(D)选项不是本段落论述依赖的假设。