could buttress
Regular verb: buttress - buttressed- buttressed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could buttress
you could buttress
she could buttress
we could buttress
you could buttress
they could buttress 	I could be buttressing
you could be buttressing
she could be buttressing
we could be buttressing
you could be buttressing
they could be buttressing	I could have buttressed
you could have buttressed
she 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
she 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 could not buttress
you could not buttress
she could not buttress
we could not buttress
you could not buttress
they could not buttress 	I could not be buttressing
you could not be buttressing
she could not be buttressing
we could not be buttressing
you could not be buttressing
they could not be buttressing	I could not have buttressed
you could not have buttressed
she could not have buttressed
we could not have buttressed
you could not have buttressed
they could not have buttressed	I could not have been buttressing
you could not have been buttressing
she could not have been buttressing
we could not have been buttressing
you could not have been buttressing
they could not have been buttressing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I buttress?
could you buttress?
could she buttress?
could we buttress?
could you buttress?
could they buttress? 	could I be buttressing?
could you be buttressing?
could she be buttressing?
could we be buttressing?
could you be buttressing?
could they be buttressing? 	could I have buttressed?
could you have buttressed?
could she 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 she 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 	
could I not buttress?
could you not buttress?
could she not buttress?
could we not buttress?
could you not buttress?
could they not buttress? 	could I not be buttressing?
could you not be buttressing?
could she not be buttressing?
could we not be buttressing?
could you not be buttressing?
could they not be buttressing? 	could I not have buttressed?
could you not have buttressed?
could she not have buttressed?
could we not have buttressed?
could you not have buttressed?
could they not have buttressed? 	could I not have been buttressing?
could you not have been buttressing?
could she not have been buttressing?
could we not have been buttressing?
could you not have been buttressing?
could they not have been buttressing?