could buttress
Regular verb: buttress - buttressed- buttressed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could buttress
you could buttress
he could buttress
we could buttress
you could buttress
they could buttress 	I could be buttressing
you could be buttressing
he could be buttressing
we could be buttressing
you could be buttressing
they could be buttressing	I could have buttressed
you could have buttressed
he could have buttressed
we could have buttressed
you could have buttressed
they could have buttressed	I could have been buttressing
you could have been buttressing
he could have been buttressing
we could have been buttressing
you could have been buttressing
they could have been buttressing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't buttress
you couldn't buttress
he couldn't buttress
we couldn't buttress
you couldn't buttress
they couldn't buttress 	I couldn't be buttressing
you couldn't be buttressing
he couldn't be buttressing
we couldn't be buttressing
you couldn't be buttressing
they couldn't be buttressing	I couldn't have buttressed
you couldn't have buttressed
he couldn't have buttressed
we couldn't have buttressed
you couldn't have buttressed
they couldn't have buttressed	I couldn't have been buttressing
you couldn't have been buttressing
he couldn't have been buttressing
we couldn't have been buttressing
you couldn't have been buttressing
they couldn't have been buttressing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I buttress?
could you buttress?
could he buttress?
could we buttress?
could you buttress?
could they buttress? 	could I be buttressing?
could you be buttressing?
could he be buttressing?
could we be buttressing?
could you be buttressing?
could they be buttressing? 	could I have buttressed?
could you have buttressed?
could he have buttressed?
could we have buttressed?
could you have buttressed?
could they have buttressed? 	could I have been buttressing?
could you have been buttressing?
could he have been buttressing?
could we have been buttressing?
could you have been buttressing?
could they have been buttressing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I buttress?
couldn't you buttress?
couldn't he buttress?
couldn't we buttress?
couldn't you buttress?
couldn't they buttress? 	couldn't I be buttressing?
couldn't you be buttressing?
couldn't he be buttressing?
couldn't we be buttressing?
couldn't you be buttressing?
couldn't they be buttressing? 	couldn't I have buttressed?
couldn't you have buttressed?
couldn't he have buttressed?
couldn't we have buttressed?
couldn't you have buttressed?
couldn't they have buttressed? 	couldn't I have been buttressing?
couldn't you have been buttressing?
couldn't he have been buttressing?
couldn't we have been buttressing?
couldn't you have been buttressing?
couldn't they have been buttressing?