must fable
Regular verb: fable - fabled- fabled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must fable
you must fable
she must fable
we must fable
you must fable
they must fable 	I must be fabling
you must be fabling
she must be fabling
we must be fabling
you must be fabling
they must be fabling	I must have fabled
you must have fabled
she must have fabled
we must have fabled
you must have fabled
they must have fabled	I must have been fabling
you must have been fabling
she must have been fabling
we must have been fabling
you must have been fabling
they must have been fabling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not fable
you must not fable
she must not fable
we must not fable
you must not fable
they must not fable 	I must not be fabling
you must not be fabling
she must not be fabling
we must not be fabling
you must not be fabling
they must not be fabling	I must not have fabled
you must not have fabled
she must not have fabled
we must not have fabled
you must not have fabled
they must not have fabled	I must not have been fabling
you must not have been fabling
she must not have been fabling
we must not have been fabling
you must not have been fabling
they must not have been fabling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I fable?
must you fable?
must she fable?
must we fable?
must you fable?
must they fable? 	must I be fabling?
must you be fabling?
must she be fabling?
must we be fabling?
must you be fabling?
must they be fabling? 	must I have fabled?
must you have fabled?
must she have fabled?
must we have fabled?
must you have fabled?
must they have fabled? 	must I have been fabling?
must you have been fabling?
must she have been fabling?
must we have been fabling?
must you have been fabling?
must they have been fabling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not fable?
must you not fable?
must she not fable?
must we not fable?
must you not fable?
must they not fable? 	must I not be fabling?
must you not be fabling?
must she not be fabling?
must we not be fabling?
must you not be fabling?
must they not be fabling? 	must I not have fabled?
must you not have fabled?
must she not have fabled?
must we not have fabled?
must you not have fabled?
must they not have fabled? 	must I not have been fabling?
must you not have been fabling?
must she not have been fabling?
must we not have been fabling?
must you not have been fabling?
must they not have been fabling?