must abstain
Verbo regular: abstain - abstained- abstained

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must abstain
you must abstain
he must abstain
we must abstain
you must abstain
they must abstain 	I must be abstaining
you must be abstaining
he must be abstaining
we must be abstaining
you must be abstaining
they must be abstaining	I must have abstained
you must have abstained
he must have abstained
we must have abstained
you must have abstained
they must have abstained	I must have been abstaining
you must have been abstaining
he must have been abstaining
we must have been abstaining
you must have been abstaining
they must have been abstaining	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not abstain
you must not abstain
he must not abstain
we must not abstain
you must not abstain
they must not abstain 	I must not be abstaining
you must not be abstaining
he must not be abstaining
we must not be abstaining
you must not be abstaining
they must not be abstaining	I must not have abstained
you must not have abstained
he must not have abstained
we must not have abstained
you must not have abstained
they must not have abstained	I must not have been abstaining
you must not have been abstaining
he must not have been abstaining
we must not have been abstaining
you must not have been abstaining
they must not have been abstaining	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I abstain?
must you abstain?
must he abstain?
must we abstain?
must you abstain?
must they abstain? 	must I be abstaining?
must you be abstaining?
must he be abstaining?
must we be abstaining?
must you be abstaining?
must they be abstaining? 	must I have abstained?
must you have abstained?
must he have abstained?
must we have abstained?
must you have abstained?
must they have abstained? 	must I have been abstaining?
must you have been abstaining?
must he have been abstaining?
must we have been abstaining?
must you have been abstaining?
must they have been abstaining? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not abstain?
must you not abstain?
must he not abstain?
must we not abstain?
must you not abstain?
must they not abstain? 	must I not be abstaining?
must you not be abstaining?
must he not be abstaining?
must we not be abstaining?
must you not be abstaining?
must they not be abstaining? 	must I not have abstained?
must you not have abstained?
must he not have abstained?
must we not have abstained?
must you not have abstained?
must they not have abstained? 	must I not have been abstaining?
must you not have been abstaining?
must he not have been abstaining?
must we not have been abstaining?
must you not have been abstaining?
must they not have been abstaining?