An investigation that is ---------- can occasionally yield new facts, even notable ones, but typically the appearance of such facts is the result of a search in a definite direction.

　　(A) timely

　　(B) unguided

　　(C) consistent

　　(D) uncomplicated

　　(E) subjective

　　〖解答〗

　　在以but连接的两个句子中分别两次涉及“研究”(investigation search)这一概念。从search后面的介词结构in a definite direction可求取其反义词(B) unguided。

　　〖中译〗

　　一种漫无目的，无的放矢式的研究偶尔能揭示出新的事实，甚至是引人瞩目的事实；但是，普遍而言，此类事实的出现是有着明确方向的探索带来的结果。