问题补充:
— Do you still remember when we went to Nanjing?
— I can remember now but sometime last summer?
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:情态动词加现在完成式,表示对过去的推测,could表可能性,should表过去该做而没做的事。