could shell
Verbo regular: shell - shelled- shelled

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could shell
you could shell
she could shell
we could shell
you could shell
they could shell 	I could be shelling
you could be shelling
she could be shelling
we could be shelling
you could be shelling
they could be shelling	I could have shelled
you could have shelled
she could have shelled
we could have shelled
you could have shelled
they could have shelled	I could have been shelling
you could have been shelling
she could have been shelling
we could have been shelling
you could have been shelling
they could have been shelling	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't shell
you couldn't shell
she couldn't shell
we couldn't shell
you couldn't shell
they couldn't shell 	I couldn't be shelling
you couldn't be shelling
she couldn't be shelling
we couldn't be shelling
you couldn't be shelling
they couldn't be shelling	I couldn't have shelled
you couldn't have shelled
she couldn't have shelled
we couldn't have shelled
you couldn't have shelled
they couldn't have shelled	I couldn't have been shelling
you couldn't have been shelling
she couldn't have been shelling
we couldn't have been shelling
you couldn't have been shelling
they couldn't have been shelling	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I shell?
could you shell?
could she shell?
could we shell?
could you shell?
could they shell? 	could I be shelling?
could you be shelling?
could she be shelling?
could we be shelling?
could you be shelling?
could they be shelling? 	could I have shelled?
could you have shelled?
could she have shelled?
could we have shelled?
could you have shelled?
could they have shelled? 	could I have been shelling?
could you have been shelling?
could she have been shelling?
could we have been shelling?
could you have been shelling?
could they have been shelling? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I shell?
couldn't you shell?
couldn't she shell?
couldn't we shell?
couldn't you shell?
couldn't they shell? 	couldn't I be shelling?
couldn't you be shelling?
couldn't she be shelling?
couldn't we be shelling?
couldn't you be shelling?
couldn't they be shelling? 	couldn't I have shelled?
couldn't you have shelled?
couldn't she have shelled?
couldn't we have shelled?
couldn't you have shelled?
couldn't they have shelled? 	couldn't I have been shelling?
couldn't you have been shelling?
couldn't she have been shelling?
couldn't we have been shelling?
couldn't you have been shelling?
couldn't they have been shelling?