English verb conjugation
COULD CORROBORATE

Regular verb: corroborate - corroborated - corroborated

Affirmation

Simple form	V-ing form
I could corroborate you could corroborate he could corroborate we could corroborate you could corroborate they could corroborate	I could be corroborating you could be corroborating he could be corroborating we could be corroborating you could be corroborating they could be corroborating
Perfect	V-ing perfect
I could have corroborated you could have corroborated he could have corroborated we could have corroborated you could have corroborated they could have corroborated	I could have been corroborating you could have been corroborating he could have been corroborating we could have been corroborating you could have been corroborating they could have been corroborating

Negation

Simple form	V-ing form
I couldn't corroborate you couldn't corroborate he couldn't corroborate we couldn't corroborate you couldn't corroborate they couldn't corroborate	I couldn't be corroborating you couldn't be corroborating he couldn't be corroborating we couldn't be corroborating you couldn't be corroborating they couldn't be corroborating
Perfect	V-ing perfect
I couldn't have corroborated you couldn't have corroborated he couldn't have corroborated we couldn't have corroborated you couldn't have corroborated they couldn't have corroborated	I couldn't have been corroborating you couldn't have been corroborating he couldn't have been corroborating we couldn't have been corroborating you couldn't have been corroborating they couldn't have been corroborating

Interrogative form

Simple form	V-ing form
could I corroborate? could you corroborate? could he corroborate? could we corroborate? could you corroborate? could they corroborate?	could I be corroborating? could you be corroborating? could he be corroborating? could we be corroborating? could you be corroborating? could they be corroborating?
Perfect	V-ing perfect
could I have corroborated? could you have corroborated? could he have corroborated? could we have corroborated? could you have corroborated? could they have corroborated?	could I have been corroborating? could you have been corroborating? could he have been corroborating? could we have been corroborating? could you have been corroborating? could they have been corroborating?

Interro-negative form

Simple form	V-ing form
couldn't I corroborate? couldn't you corroborate? couldn't he corroborate? couldn't we corroborate? couldn't you corroborate? couldn't they corroborate?	couldn't I be corroborating? couldn't you be corroborating? couldn't he be corroborating? couldn't we be corroborating? couldn't you be corroborating? couldn't they be corroborating?
Perfect	V-ing perfect
couldn't I have corroborated? couldn't you have corroborated? couldn't he have corroborated? couldn't we have corroborated? couldn't you have corroborated? couldn't they have corroborated?	couldn't I have been corroborating? couldn't you have been corroborating? couldn't he have been corroborating? couldn't we have been corroborating? couldn't you have been corroborating? couldn't they have been corroborating?