—— 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

—— 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

—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

—— Do you still remember the day when we went to the Great Wall?

—— I can’t remember it well, but＿＿＿＿＿＿sometime last autumn?

1. A.
   might it be
2. B.
   could it have been
3. C.
   could it be
4. D.
   must it have been