must substitute
Verbo regular: substitute - substituted- substituted

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must substitute
you must substitute
he must substitute
we must substitute
you must substitute
they must substitute 	I must be substituting
you must be substituting
he must be substituting
we must be substituting
you must be substituting
they must be substituting	I must have substituted
you must have substituted
he must have substituted
we must have substituted
you must have substituted
they must have substituted	I must have been substituting
you must have been substituting
he must have been substituting
we must have been substituting
you must have been substituting
they must have been substituting	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not substitute
you must not substitute
he must not substitute
we must not substitute
you must not substitute
they must not substitute 	I must not be substituting
you must not be substituting
he must not be substituting
we must not be substituting
you must not be substituting
they must not be substituting	I must not have substituted
you must not have substituted
he must not have substituted
we must not have substituted
you must not have substituted
they must not have substituted	I must not have been substituting
you must not have been substituting
he must not have been substituting
we must not have been substituting
you must not have been substituting
they must not have been substituting	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I substitute?
must you substitute?
must he substitute?
must we substitute?
must you substitute?
must they substitute? 	must I be substituting?
must you be substituting?
must he be substituting?
must we be substituting?
must you be substituting?
must they be substituting? 	must I have substituted?
must you have substituted?
must he have substituted?
must we have substituted?
must you have substituted?
must they have substituted? 	must I have been substituting?
must you have been substituting?
must he have been substituting?
must we have been substituting?
must you have been substituting?
must they have been substituting? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not substitute?
must you not substitute?
must he not substitute?
must we not substitute?
must you not substitute?
must they not substitute? 	must I not be substituting?
must you not be substituting?
must he not be substituting?
must we not be substituting?
must you not be substituting?
must they not be substituting? 	must I not have substituted?
must you not have substituted?
must he not have substituted?
must we not have substituted?
must you not have substituted?
must they not have substituted? 	must I not have been substituting?
must you not have been substituting?
must he not have been substituting?
must we not have been substituting?
must you not have been substituting?
must they not have been substituting?