It was playing computer games cost the boy plenty of time he ought to have spent doing his

问题补充：

It was playing computer games cost the boy plenty of time he ought to have spent doing his homework.

A. that; that

B. which; that

C. which; when

D. that; when

答案：

(答案→)A. that; that

B. which; that

C. which; when

D. that; when

解析：这题考查强调句，强调的是playing computer games，第二空考查定语从句，先行词是plenty of time，定语从句中缺乏宾语用that引导句意是：就是玩电脑游戏花了男孩本来应该花来写作业的时间。选A。