The boss____________ the worker how to do it, or the accident couldn't have happened.
A. can't have told B. ought to tell
C. could have told D. mustn't have told
The boss____________ the worker how to do it, or the accident couldn't have happened.
A. can't have told B. ought to tell
C. could have told D. mustn't have told
A
抓住关键“or”，意为“否则”，所以前后意思相反。