---How did you do in the test yesterday?
-----Not so well. I much better but I misread the directions for writing。
A. will have done
B. could have done
C. must have done
D. may have done
网友回答
A. will have done
(答案→)B. could have done
C. must have done
D. may have done
解析：考查虚拟语气。ACD三项都不能用来表示虚拟语气。句意：—在昨天的考试中你表现怎么样?—不是很好。我本可以做得更好，但是我看错了写作的要求。Could have done本可以做，实际上却未做。故B正确。