语法与词汇 14.Upon arriving home, I was surprised to find the paper I had had______was missing.
【正确答案】 D
【答案解析】句意：我一到家就惊奇地发现我事先让人准备的文件不见了。(that／which)I had had prepared是定语从句，修饰先行词the paper，从句中含有一个have sth．done结构，表示“让别人做某事”，故选D。