could serve
Verbo regular: serve - served- served

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could serve
you could serve
he could serve
we could serve
you could serve
they could serve 	I could be serving
you could be serving
he could be serving
we could be serving
you could be serving
they could be serving	I could have served
you could have served
he could have served
we could have served
you could have served
they could have served	I could have been serving
you could have been serving
he could have been serving
we could have been serving
you could have been serving
they could have been serving	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't serve
you couldn't serve
he couldn't serve
we couldn't serve
you couldn't serve
they couldn't serve 	I couldn't be serving
you couldn't be serving
he couldn't be serving
we couldn't be serving
you couldn't be serving
they couldn't be serving	I couldn't have served
you couldn't have served
he couldn't have served
we couldn't have served
you couldn't have served
they couldn't have served	I couldn't have been serving
you couldn't have been serving
he couldn't have been serving
we couldn't have been serving
you couldn't have been serving
they couldn't have been serving	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I serve?
could you serve?
could he serve?
could we serve?
could you serve?
could they serve? 	could I be serving?
could you be serving?
could he be serving?
could we be serving?
could you be serving?
could they be serving? 	could I have served?
could you have served?
could he have served?
could we have served?
could you have served?
could they have served? 	could I have been serving?
could you have been serving?
could he have been serving?
could we have been serving?
could you have been serving?
could they have been serving? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I serve?
couldn't you serve?
couldn't he serve?
couldn't we serve?
couldn't you serve?
couldn't they serve? 	couldn't I be serving?
couldn't you be serving?
couldn't he be serving?
couldn't we be serving?
couldn't you be serving?
couldn't they be serving? 	couldn't I have served?
couldn't you have served?
couldn't he have served?
couldn't we have served?
couldn't you have served?
couldn't they have served? 	couldn't I have been serving?
couldn't you have been serving?
couldn't he have been serving?
couldn't we have been serving?
couldn't you have been serving?
couldn't they have been serving?