must corroborate
Regular verb: corroborate - corroborated- corroborated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must corroborate
you must corroborate
he must corroborate
we must corroborate
you must corroborate
they must corroborate 	I must be corroborating
you must be corroborating
he must be corroborating
we must be corroborating
you must be corroborating
they must be corroborating	I must have corroborated
you must have corroborated
he must have corroborated
we must have corroborated
you must have corroborated
they must have corroborated	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 	V-ing form 	Perfect 	V-ing perfect 	
I must not corroborate
you must not corroborate
he must not corroborate
we must not corroborate
you must not corroborate
they must not corroborate 	I must not be corroborating
you must not be corroborating
he must not be corroborating
we must not be corroborating
you must not be corroborating
they must not be corroborating	I must not have corroborated
you must not have corroborated
he must not have corroborated
we must not have corroborated
you must not have corroborated
they must not have corroborated	I must not have been corroborating
you must not have been corroborating
he must not have been corroborating
we must not have been corroborating
you must not have been corroborating
they must not have been corroborating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I corroborate?
must you corroborate?
must he corroborate?
must we corroborate?
must you corroborate?
must they corroborate? 	must I be corroborating?
must you be corroborating?
must he be corroborating?
must we be corroborating?
must you be corroborating?
must they be corroborating? 	must I have corroborated?
must you have corroborated?
must he have corroborated?
must we have corroborated?
must you have corroborated?
must they have corroborated? 	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 	V-ing form 	Perfect 	V-ing perfect 	
must I not corroborate?
must you not corroborate?
must he not corroborate?
must we not corroborate?
must you not corroborate?
must they not corroborate? 	must I not be corroborating?
must you not be corroborating?
must he not be corroborating?
must we not be corroborating?
must you not be corroborating?
must they not be corroborating? 	must I not have corroborated?
must you not have corroborated?
must he not have corroborated?
must we not have corroborated?
must you not have corroborated?
must they not have corroborated? 	must I not have been corroborating?
must you not have been corroborating?
must he not have been corroborating?
must we not have been corroborating?
must you not have been corroborating?
must they not have been corroborating?