题目

金刚烷（C10H16）是一种重要的脂肪烷烃，其结构高度对称，如右图所示。金刚烷能与卤素发生取代反应，其中一氯 一溴金刚烷（C10H14ClBr）的同分异构体数目是 A.4种 B.6种   C.8种   D.10种 答案：C －Oh, Miss Wang．Your skirt looks nice．Is it new? －No, I ________ it for three years． [　　] A． had B． have bought C． have had D． bought