一道真题

Which of the following best completes the passage below?

Monarch butterflies, whose average life span is nine months, migrate from the midwestern United States to selected forests outside Mexico City. It takes at least three generations of monarchs to make the journey, so the great-great-grandchildren who finally arrive in the Mexican forests have never been there before. Yet they return to the same trees their forebears left. Scientists theorize that monarchs, like homing pigeons, map their routes according to the earth’s electromagnetic fields. As a first step in testing this theory, lepidopterists plan to install a low-voltage transmitter inside one grove of “butterfly trees” in the Mexican forests. If the butterflies are either especially attracted to the grove with the transmitter or especially repelled by it, lepidopterists will have evidence that______

(A) monarch butterflies have brains, however minuscule

(B) monarch butterflies are sensitive to electricity

(C) low-voltage electricity can affect butterflies, whether positively or adversely

(D) monarchs map their routes according to the earth’s electromagnetic fields

(E) monarchs communicate in intergenerationally via electromagnetic fields

请教大牛， 这里的d为什么不对？ 谢谢！！

请问楼主，这题是那里的题？

讨论链接里不知道有没有讨论。

As a first step in testing this theory. 所以D应该是不正确的，尽管D很容易被认为正确选项。

正确选项应该是If the butterflies are either especially attracted to the grove with the transmitter or especially repelled by it,能够推出的。我觉得应该B是最佳选择。不知道答案是什么？

支持HOWARDWANG。

只有B/D有比较的可能。B是能从提干中，特别是最后一句IF中推出的，很直接；B是最后的要验证的结论，文中没有足够桥梁。