Most of the students felt rather disappointed at the English party. They say that it better organized.
A. had been
B. had to be
C. must have been
D. could have been
网友回答
A. had been
B. had to be
C. must have been
(答案→)D. could have been
解析：could have done sth. 表示“本来能够做某事而实际上未能做成”。