—You know that you were driving at 100 kilometres per hour, don't you?
—No, officer, I ________have been.This car can't do more than 80.
A.mustn't B.shouldn't
C.may not D.couldn't
—You know that you were driving at 100 kilometres per hour, don't you?
—No, officer, I ________have been.This car can't do more than 80.
A.mustn't B.shouldn't
C.may not D.couldn't
D [couldn't have done是对过去的否定推测。]