it was playing computer games that cost the boy plenty of time that he doing his lessons
情态动词的选择 might have spent must have spent could have spent ought to have spent 为什么ought 后面加这个 to 为什么其他的不用加 他玩游戏花费了大量他本该做作业的时间 顺便把话费的四个句型给我说下吧