单选题 How did the science of preparing metals for use happen?

【正确答案】 B
【答案解析】[精解] 文章细节题。浏览全文,就可以找到"…it(the science of preparing metal for use)happened more by chance than by any planned purpose…",这与选项[B](偶然)说法完全一样,因此选项[B]正确.