could dull
Verbo regular: dull - dulled- dulled

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could dull
you could dull
she could dull
we could dull
you could dull
they could dull 	I could be dulling
you could be dulling
she could be dulling
we could be dulling
you could be dulling
they could be dulling	I could have dulled
you could have dulled
she could have dulled
we could have dulled
you could have dulled
they could have dulled	I could have been dulling
you could have been dulling
she could have been dulling
we could have been dulling
you could have been dulling
they could have been dulling	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not dull
you could not dull
she could not dull
we could not dull
you could not dull
they could not dull 	I could not be dulling
you could not be dulling
she could not be dulling
we could not be dulling
you could not be dulling
they could not be dulling	I could not have dulled
you could not have dulled
she could not have dulled
we could not have dulled
you could not have dulled
they could not have dulled	I could not have been dulling
you could not have been dulling
she could not have been dulling
we could not have been dulling
you could not have been dulling
they could not have been dulling	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I dull?
could you dull?
could she dull?
could we dull?
could you dull?
could they dull? 	could I be dulling?
could you be dulling?
could she be dulling?
could we be dulling?
could you be dulling?
could they be dulling? 	could I have dulled?
could you have dulled?
could she have dulled?
could we have dulled?
could you have dulled?
could they have dulled? 	could I have been dulling?
could you have been dulling?
could she have been dulling?
could we have been dulling?
could you have been dulling?
could they have been dulling? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not dull?
could you not dull?
could she not dull?
could we not dull?
could you not dull?
could they not dull? 	could I not be dulling?
could you not be dulling?
could she not be dulling?
could we not be dulling?
could you not be dulling?
could they not be dulling? 	could I not have dulled?
could you not have dulled?
could she not have dulled?
could we not have dulled?
could you not have dulled?
could they not have dulled? 	could I not have been dulling?
could you not have been dulling?
could she not have been dulling?
could we not have been dulling?
could you not have been dulling?
could they not have been dulling?