-- Do you still remember the day when we went to the Great Wall? -- I can’t reme
来源：网络
时间：
推荐文章
—— Do you still remember the day when we went to the Great Wall?
—— I can’t remember it well, but＿＿＿＿＿＿sometime last autumn?
A. might it be B. could it have been C. could it be D. must it have been
试题答案
B
解析:
could have done表示对过去发生情况的可能性推测。