Question

It was playing computer games that cost the boy plenty of time that he _______ have spent doing his lessons.?
A.might  B.must C.ought to D.could

Answer 1

C

ought to/should have done表責備，意為“應該做（而未做）”，might have done表示“可能已經做了”。must have done 表示“一定做了，”could have done 指“本來能做而沒有做”。
根據(jù)句意“正是玩電腦游戲花了這男孩大量本應花在功課上的時間”可知應該用ought to。