26．—Do you still remember the day when we went to the Great Wall?
—I can't remember it well, but ________ it have been sometime last year?
A. would B. must
C. could D. should
[解析]本题考查“情态动词＋have done”。句意：—你还记得我们去长城的那一天吗？—我记不太清了，是不是去年的某个时候？由语境可知，这是对过去某个时间的推测，并且用于疑问句，故只能选 could。
[答案]C
27．What a pity! Considering his intelligence and diligence, he ________ a higher grade.
A. can have achieved B. must have achieved
C. need have achieved D. might have achieved
[解析]本题考查“情态动词＋have done”。can have done“过去可能干过”，一般不用于肯定的陈述句；must have done，“过去肯定干过”；might have done 意义有两层：一表示“过去可能干过某事”；二表示“过去本可能干某事而事实上没干”；由句意“真遗憾！鉴于他的智力和努力，他本来能够获得一个更高一点的分数”可知D项正确。
[答案]D
