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题库 / GmatLaCourse-SC-62
By sucking sap from the young twigs of the hemlock tree, tree growth is retarded by the woolly adelgid, which causes needles to change color from deep green to grayish green and to drop prematurely.
tree growth is retarded by the woolly adelgid, which causes needles to change color from deep green to grayish green and to drop
the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop
tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop
略
略
题目分析：
能吮吸sap的肯定是the woolly adelgid，而不是树木的增长，答案为(B)。