could retrogress
Verbo regular: retrogress - retrogressed- retrogressed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could retrogress
you could retrogress
he could retrogress
we could retrogress
you could retrogress
they could retrogress 	I could be retrogressing
you could be retrogressing
he could be retrogressing
we could be retrogressing
you could be retrogressing
they could be retrogressing	I could have retrogressed
you could have retrogressed
he could have retrogressed
we could have retrogressed
you could have retrogressed
they could have retrogressed	I could have been retrogressing
you could have been retrogressing
he could have been retrogressing
we could have been retrogressing
you could have been retrogressing
they could have been retrogressing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't retrogress
you couldn't retrogress
he couldn't retrogress
we couldn't retrogress
you couldn't retrogress
they couldn't retrogress 	I couldn't be retrogressing
you couldn't be retrogressing
he couldn't be retrogressing
we couldn't be retrogressing
you couldn't be retrogressing
they couldn't be retrogressing	I couldn't have retrogressed
you couldn't have retrogressed
he couldn't have retrogressed
we couldn't have retrogressed
you couldn't have retrogressed
they couldn't have retrogressed	I couldn't have been retrogressing
you couldn't have been retrogressing
he couldn't have been retrogressing
we couldn't have been retrogressing
you couldn't have been retrogressing
they couldn't have been retrogressing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I retrogress?
could you retrogress?
could he retrogress?
could we retrogress?
could you retrogress?
could they retrogress? 	could I be retrogressing?
could you be retrogressing?
could he be retrogressing?
could we be retrogressing?
could you be retrogressing?
could they be retrogressing? 	could I have retrogressed?
could you have retrogressed?
could he have retrogressed?
could we have retrogressed?
could you have retrogressed?
could they have retrogressed? 	could I have been retrogressing?
could you have been retrogressing?
could he have been retrogressing?
could we have been retrogressing?
could you have been retrogressing?
could they have been retrogressing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I retrogress?
couldn't you retrogress?
couldn't he retrogress?
couldn't we retrogress?
couldn't you retrogress?
couldn't they retrogress? 	couldn't I be retrogressing?
couldn't you be retrogressing?
couldn't he be retrogressing?
couldn't we be retrogressing?
couldn't you be retrogressing?
couldn't they be retrogressing? 	couldn't I have retrogressed?
couldn't you have retrogressed?
couldn't he have retrogressed?
couldn't we have retrogressed?
couldn't you have retrogressed?
couldn't they have retrogressed? 	couldn't I have been retrogressing?
couldn't you have been retrogressing?
couldn't he have been retrogressing?
couldn't we have been retrogressing?
couldn't you have been retrogressing?
couldn't they have been retrogressing?