— You don’t forget when we borrowed that reference book do you?— I can’t remember now but

问题补充：

— You don’t forget when we borrowed that reference book, do you?

— I can’t remember now but sometime last week?

A. might it be

B. could it be

C. could it have been

D. should it have been

答案：

A. might it be

B. could it be

(答案→)C. could it have been

D. should it have been

解析：考查情态动词。句意为“你想不起是什么时间借的那本参考书啦，对吗？我现在不记得啦，可能是上周的某个时间吧。”情态动词+完成时态表示对过去的推测.could表示可能性；should表示过去该做而没有做的事。表示可能性的用法是高考必考点之一。