Was it in 1998,when he was still at middle school,______ this boy became an expert at computer?
问题描述：
Was it in 1998,when he was still at middle school,______ this boy became an expert at computer?
A.which B.where C.that D.when
答
选C,强调句的疑问形式.when he was still at middle school是定语从句,修饰1998原句可以看成 Was it in 1998 （that） this boy became an expert at computer?陈述句为It was in 1998 （that） this boy became an ...