问题
选择题
It was playing computer games that cost the boy plenty of time he ____ doing his lessons.
A．might have spent
B．ought to have spent
C．must have spent
D．could have spent
答案
答案：B
本题考查的是虚拟语气的有关用法。Ought to / should + have +p.p表示“本来应该做却没有做到的事情”，有责备的含义。