【题目】It was only after he had read the papers ________ Mr. Gross realized the task before him was extremely difficult to complete.
A．when B. that
C. which D. what
在线课程【答案】B
【解析】
试题分析：考查强调句型。句意：只有在读了这些文件后，格罗斯先生才认识到他面临着的任务很难完成。此句是对only引导的时间状语从句的强调。省略了it was…that之后，句子结构完整。