must abstain
Verbo regular: abstain - abstained- abstained

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must abstain
you must abstain
she must abstain
we must abstain
you must abstain
they must abstain 	I must be abstaining
you must be abstaining
she must be abstaining
we must be abstaining
you must be abstaining
they must be abstaining	I must have abstained
you must have abstained
she 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
she must have been abstaining
we must have been abstaining
you must have been abstaining
they must have been abstaining	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must not abstain
you must not abstain
she 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
she 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
she 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
she 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 com V-ing 	Perfeito 	Perfeito com V-ing 	
must I abstain?
must you abstain?
must she abstain?
must we abstain?
must you abstain?
must they abstain? 	must I be abstaining?
must you be abstaining?
must she be abstaining?
must we be abstaining?
must you be abstaining?
must they be abstaining? 	must I have abstained?
must you have abstained?
must she 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 she have been abstaining?
must we have been abstaining?
must you have been abstaining?
must they have been abstaining? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I not abstain?
must you not abstain?
must she 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 she 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 she 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 she not have been abstaining?
must we not have been abstaining?
must you not have been abstaining?
must they not have been abstaining?