must buttress
Verbo regular: buttress - buttressed- buttressed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must buttress
you must buttress
he must buttress
we must buttress
you must buttress
they must buttress 	I must be buttressing
you must be buttressing
he must be buttressing
we must be buttressing
you must be buttressing
they must be buttressing	I must have buttressed
you must have buttressed
he must have buttressed
we must have buttressed
you must have buttressed
they must have buttressed	I must have been buttressing
you must have been buttressing
he must have been buttressing
we must have been buttressing
you must have been buttressing
they must have been buttressing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not buttress
you must not buttress
he must not buttress
we must not buttress
you must not buttress
they must not buttress 	I must not be buttressing
you must not be buttressing
he must not be buttressing
we must not be buttressing
you must not be buttressing
they must not be buttressing	I must not have buttressed
you must not have buttressed
he must not have buttressed
we must not have buttressed
you must not have buttressed
they must not have buttressed	I must not have been buttressing
you must not have been buttressing
he must not have been buttressing
we must not have been buttressing
you must not have been buttressing
they must not have been buttressing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I buttress?
must you buttress?
must he buttress?
must we buttress?
must you buttress?
must they buttress? 	must I be buttressing?
must you be buttressing?
must he be buttressing?
must we be buttressing?
must you be buttressing?
must they be buttressing? 	must I have buttressed?
must you have buttressed?
must he have buttressed?
must we have buttressed?
must you have buttressed?
must they have buttressed? 	must I have been buttressing?
must you have been buttressing?
must he have been buttressing?
must we have been buttressing?
must you have been buttressing?
must they have been buttressing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not buttress?
must you not buttress?
must he not buttress?
must we not buttress?
must you not buttress?
must they not buttress? 	must I not be buttressing?
must you not be buttressing?
must he not be buttressing?
must we not be buttressing?
must you not be buttressing?
must they not be buttressing? 	must I not have buttressed?
must you not have buttressed?
must he not have buttressed?
must we not have buttressed?
must you not have buttressed?
must they not have buttressed? 	must I not have been buttressing?
must you not have been buttressing?
must he not have been buttressing?
must we not have been buttressing?
must you not have been buttressing?
must they not have been buttressing?