I must corroborate you must corroborate he must corroborate we must corroborate you must corroborate they must corroborate
V-ing form
I must be corroborating you must be corroborating he must be corroborating we must be corroborating you must be corroborating they must be corroborating
Perfect
I must have corroborated you must have corroborated he must have corroborated we must have corroborated you must have corroborated they must have corroborated
V-ing perfect
I must have been corroborating you must have been corroborating he must have been corroborating we must have been corroborating you must have been corroborating they must have been corroborating
Negation
Simple form
I mustn't corroborate you mustn't corroborate he mustn't corroborate we mustn't corroborate you mustn't corroborate they mustn't corroborate
V-ing form
I mustn't be corroborating you mustn't be corroborating he mustn't be corroborating we mustn't be corroborating you mustn't be corroborating they mustn't be corroborating
Perfect
I mustn't have corroborated you mustn't have corroborated he mustn't have corroborated we mustn't have corroborated you mustn't have corroborated they mustn't have corroborated
V-ing perfect
I mustn't have been corroborating you mustn't have been corroborating he mustn't have been corroborating we mustn't have been corroborating you mustn't have been corroborating they mustn't have been corroborating
Interrogative form
Simple form
must I corroborate? must you corroborate? must he corroborate? must we corroborate? must you corroborate? must they corroborate?
V-ing form
must I be corroborating? must you be corroborating? must he be corroborating? must we be corroborating? must you be corroborating? must they be corroborating?
Perfect
must I have corroborated? must you have corroborated? must he have corroborated? must we have corroborated? must you have corroborated? must they have corroborated?
V-ing perfect
must I have been corroborating? must you have been corroborating? must he have been corroborating? must we have been corroborating? must you have been corroborating? must they have been corroborating?
Interro-negative form
Simple form
mustn't I corroborate? mustn't you corroborate? mustn't he corroborate? mustn't we corroborate? mustn't you corroborate? mustn't they corroborate?
V-ing form
mustn't I be corroborating? mustn't you be corroborating? mustn't he be corroborating? mustn't we be corroborating? mustn't you be corroborating? mustn't they be corroborating?
Perfect
mustn't I have corroborated? mustn't you have corroborated? mustn't he have corroborated? mustn't we have corroborated? mustn't you have corroborated? mustn't they have corroborated?
V-ing perfect
mustn't I have been corroborating? mustn't you have been corroborating? mustn't he have been corroborating? mustn't we have been corroborating? mustn't you have been corroborating? mustn't they have been corroborating?