He the test again, in which case, his mother will be very disappointed.
A. might fail
B. must have failed
C. should fail
D. could have failed
网友回答
(答案→)A. might fail
B. must have failed
C. should fail
D. could have failed
解析：根据下文的 will be 可知，“他考试再不及格”是将来的事，据此可排除B和D。再根据语意，排除C。