--Don't be so disappointed.I’m sure that you can do better in the next exam.
--Yes, but I this time.
A. should be more careful
B. could be more careful
C. should have been more careful
D. must have been more carefully
网友回答
A. should be more careful
B. could be more careful
(答案→)C. should have been more careful
D. must have been more carefully
解析：should have done是常用句型，意思是：本应……