请教英语高手一道关于情态动词的题目
问题描述：
请教英语高手一道关于情态动词的题目
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.would it be D.must it have been
请问哪个是正确答案?
希望大家可以告诉我为什么选择那一项？
答
因为时间状语是last autumn 先把AC排除.
must have done 一定做过某事
B
could have done/been 在过去某个时候的可能