It was playing video games that took the boy too much time that hehave spent learningA. c

问题补充：

It was playing video games that took the boy too much time that hehave spent learning．

A. could

B. must

C. might

D. ought to

答案：

A. could

B. must

C. might

(答案→)D. ought to

解析：句意：就是玩游戏花了这个男孩太多的本应该学习的时间。Ought to have done“本应该做却没有做”，could have done“本来可能会做”，must have done“过去一定会做”，might have done“本来可能会做”，所以D。