LSAT-6-3-3

3.     Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Brazil, 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.（D）

(E) The rate of increase of the fire-ant population would not exceed the rate at which the predator insects could kill the ants.

这题为什么选（D）呢？（B）为什么不可以呢？如果从Brazil引进的predator insects在美国南部的环境下根本无法存活的话，何谈去控制fire-ant population的增长呢？这题的关键是在哪里呢？

D是对部分结论的重复，为啥会是结论？

   Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Brazil, 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.

至于为啥不选B你自己说得很清楚呀

问题是哪一个不是假设。

Each of the following is an assumption made in the argument EXCEPT：

天，原来是这样啊，竟然看错题了，没想过原来假设题也可以出现EXCEPT啊

嗯，谢谢了：）