can buttress
Regular verb: buttress - buttressed- buttressed

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

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

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

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