问题补充:
How lucky he was! He involved in the murder.
A. must have been
B. can have been
C. could have been
D. would have been
答案:
A. must have been
B. can have been
(答案→)C. could have been
D. would have been
解析:句意:他好幸运啊!他本来是被牵扯进谋杀案的。could have been本能够做某事,而实际没有做,故选C