must maintain
Verbo regular: maintain - maintained- maintained

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must maintain
you must maintain
he must maintain
we must maintain
you must maintain
they must maintain 	I must be maintaining
you must be maintaining
he must be maintaining
we must be maintaining
you must be maintaining
they must be maintaining	I must have maintained
you must have maintained
he must have maintained
we must have maintained
you must have maintained
they must have maintained	I must have been maintaining
you must have been maintaining
he must have been maintaining
we must have been maintaining
you must have been maintaining
they must have been maintaining	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not maintain
you must not maintain
he must not maintain
we must not maintain
you must not maintain
they must not maintain 	I must not be maintaining
you must not be maintaining
he must not be maintaining
we must not be maintaining
you must not be maintaining
they must not be maintaining	I must not have maintained
you must not have maintained
he must not have maintained
we must not have maintained
you must not have maintained
they must not have maintained	I must not have been maintaining
you must not have been maintaining
he must not have been maintaining
we must not have been maintaining
you must not have been maintaining
they must not have been maintaining	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I maintain?
must you maintain?
must he maintain?
must we maintain?
must you maintain?
must they maintain? 	must I be maintaining?
must you be maintaining?
must he be maintaining?
must we be maintaining?
must you be maintaining?
must they be maintaining? 	must I have maintained?
must you have maintained?
must he have maintained?
must we have maintained?
must you have maintained?
must they have maintained? 	must I have been maintaining?
must you have been maintaining?
must he have been maintaining?
must we have been maintaining?
must you have been maintaining?
must they have been maintaining? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not maintain?
must you not maintain?
must he not maintain?
must we not maintain?
must you not maintain?
must they not maintain? 	must I not be maintaining?
must you not be maintaining?
must he not be maintaining?
must we not be maintaining?
must you not be maintaining?
must they not be maintaining? 	must I not have maintained?
must you not have maintained?
must he not have maintained?
must we not have maintained?
must you not have maintained?
must they not have maintained? 	must I not have been maintaining?
must you not have been maintaining?
must he not have been maintaining?
must we not have been maintaining?
must you not have been maintaining?
must they not have been maintaining?