Was it in 1997he was still at middle school this boy became an expert at computer?A. that;

问题补充：

Was it in 1997he was still at middle school this boy became an expert at computer?

A. that; where

B. when; where

C. in which; in which

D. when; that

答案：

A. that; where

B. when; where

C. in which; in which

(答案→)D. when; that

解析：句意：那是在1997年他在中学的时候，这个男孩成了电脑专家。这里是强调句型，其结构是It was+被强调部分+ that+其他，判断强调句型的方法是把It was that去掉整个句子不缺成分，是成立的。这里被强调部分是in 1997；第一空是when引导的定语从句，when he was still at middle school，它在从句中作状语，修饰前面时间；第二空是强调句型中的that，故选D。