could corroborate
Verbo regular: corroborate - corroborated- corroborated

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
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	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	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
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	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	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
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? 	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? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
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? 	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?