could quarterback
Verbo regular: quarterback - quarterbacked- quarterbacked

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could quarterback
you could quarterback
he could quarterback
we could quarterback
you could quarterback
they could quarterback 	I could be quarterbacking
you could be quarterbacking
he could be quarterbacking
we could be quarterbacking
you could be quarterbacking
they could be quarterbacking	I could have quarterbacked
you could have quarterbacked
he could have quarterbacked
we could have quarterbacked
you could have quarterbacked
they could have quarterbacked	I could have been quarterbacking
you could have been quarterbacking
he could have been quarterbacking
we could have been quarterbacking
you could have been quarterbacking
they could have been quarterbacking	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't quarterback
you couldn't quarterback
he couldn't quarterback
we couldn't quarterback
you couldn't quarterback
they couldn't quarterback 	I couldn't be quarterbacking
you couldn't be quarterbacking
he couldn't be quarterbacking
we couldn't be quarterbacking
you couldn't be quarterbacking
they couldn't be quarterbacking	I couldn't have quarterbacked
you couldn't have quarterbacked
he couldn't have quarterbacked
we couldn't have quarterbacked
you couldn't have quarterbacked
they couldn't have quarterbacked	I couldn't have been quarterbacking
you couldn't have been quarterbacking
he couldn't have been quarterbacking
we couldn't have been quarterbacking
you couldn't have been quarterbacking
they couldn't have been quarterbacking	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I quarterback?
could you quarterback?
could he quarterback?
could we quarterback?
could you quarterback?
could they quarterback? 	could I be quarterbacking?
could you be quarterbacking?
could he be quarterbacking?
could we be quarterbacking?
could you be quarterbacking?
could they be quarterbacking? 	could I have quarterbacked?
could you have quarterbacked?
could he have quarterbacked?
could we have quarterbacked?
could you have quarterbacked?
could they have quarterbacked? 	could I have been quarterbacking?
could you have been quarterbacking?
could he have been quarterbacking?
could we have been quarterbacking?
could you have been quarterbacking?
could they have been quarterbacking? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I quarterback?
couldn't you quarterback?
couldn't he quarterback?
couldn't we quarterback?
couldn't you quarterback?
couldn't they quarterback? 	couldn't I be quarterbacking?
couldn't you be quarterbacking?
couldn't he be quarterbacking?
couldn't we be quarterbacking?
couldn't you be quarterbacking?
couldn't they be quarterbacking? 	couldn't I have quarterbacked?
couldn't you have quarterbacked?
couldn't he have quarterbacked?
couldn't we have quarterbacked?
couldn't you have quarterbacked?
couldn't they have quarterbacked? 	couldn't I have been quarterbacking?
couldn't you have been quarterbacking?
couldn't he have been quarterbacking?
couldn't we have been quarterbacking?
couldn't you have been quarterbacking?
couldn't they have been quarterbacking?