It was only after he had read the papers Mr.Gross realized the task before him was extrem

问题补充：

It was only after he had read the papers Mr.Gross realized the task before him was extremely difficult to complete. (·大纲全国，30)

A. when

B. that

C. which

D. what

答案：

A. when

(答案→)B. that

C. which

D. what

解析：B

解析句意为：直到他读了文件之后，格罗斯先生才意识到他面临的任务很难完成。本句为强调句型，强调了时间状语only after he had read the papers。根据强调句结构“It is/was＋被强调部分＋that＋剩余部分”可知选B项。