must chair
Verbo regular: chair - chaired- chaired

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must chair
you must chair
he must chair
we must chair
you must chair
they must chair 	I must be chairing
you must be chairing
he must be chairing
we must be chairing
you must be chairing
they must be chairing	I must have chaired
you must have chaired
he must have chaired
we must have chaired
you must have chaired
they must have chaired	I must have been chairing
you must have been chairing
he must have been chairing
we must have been chairing
you must have been chairing
they must have been chairing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not chair
you must not chair
he must not chair
we must not chair
you must not chair
they must not chair 	I must not be chairing
you must not be chairing
he must not be chairing
we must not be chairing
you must not be chairing
they must not be chairing	I must not have chaired
you must not have chaired
he must not have chaired
we must not have chaired
you must not have chaired
they must not have chaired	I must not have been chairing
you must not have been chairing
he must not have been chairing
we must not have been chairing
you must not have been chairing
they must not have been chairing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I chair?
must you chair?
must he chair?
must we chair?
must you chair?
must they chair? 	must I be chairing?
must you be chairing?
must he be chairing?
must we be chairing?
must you be chairing?
must they be chairing? 	must I have chaired?
must you have chaired?
must he have chaired?
must we have chaired?
must you have chaired?
must they have chaired? 	must I have been chairing?
must you have been chairing?
must he have been chairing?
must we have been chairing?
must you have been chairing?
must they have been chairing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not chair?
must you not chair?
must he not chair?
must we not chair?
must you not chair?
must they not chair? 	must I not be chairing?
must you not be chairing?
must he not be chairing?
must we not be chairing?
must you not be chairing?
must they not be chairing? 	must I not have chaired?
must you not have chaired?
must he not have chaired?
must we not have chaired?
must you not have chaired?
must they not have chaired? 	must I not have been chairing?
must you not have been chairing?
must he not have been chairing?
must we not have been chairing?
must you not have been chairing?
must they not have been chairing?