must fribble
Regular verb: fribble - fribbled- fribbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must fribble
you must fribble
she must fribble
we must fribble
you must fribble
they must fribble 	I must be fribbling
you must be fribbling
she must be fribbling
we must be fribbling
you must be fribbling
they must be fribbling	I must have fribbled
you must have fribbled
she must have fribbled
we must have fribbled
you must have fribbled
they must have fribbled	I must have been fribbling
you must have been fribbling
she must have been fribbling
we must have been fribbling
you must have been fribbling
they must have been fribbling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not fribble
you must not fribble
she must not fribble
we must not fribble
you must not fribble
they must not fribble 	I must not be fribbling
you must not be fribbling
she must not be fribbling
we must not be fribbling
you must not be fribbling
they must not be fribbling	I must not have fribbled
you must not have fribbled
she must not have fribbled
we must not have fribbled
you must not have fribbled
they must not have fribbled	I must not have been fribbling
you must not have been fribbling
she must not have been fribbling
we must not have been fribbling
you must not have been fribbling
they must not have been fribbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I fribble?
must you fribble?
must she fribble?
must we fribble?
must you fribble?
must they fribble? 	must I be fribbling?
must you be fribbling?
must she be fribbling?
must we be fribbling?
must you be fribbling?
must they be fribbling? 	must I have fribbled?
must you have fribbled?
must she have fribbled?
must we have fribbled?
must you have fribbled?
must they have fribbled? 	must I have been fribbling?
must you have been fribbling?
must she have been fribbling?
must we have been fribbling?
must you have been fribbling?
must they have been fribbling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not fribble?
must you not fribble?
must she not fribble?
must we not fribble?
must you not fribble?
must they not fribble? 	must I not be fribbling?
must you not be fribbling?
must she not be fribbling?
must we not be fribbling?
must you not be fribbling?
must they not be fribbling? 	must I not have fribbled?
must you not have fribbled?
must she not have fribbled?
must we not have fribbled?
must you not have fribbled?
must they not have fribbled? 	must I not have been fribbling?
must you not have been fribbling?
must she not have been fribbling?
must we not have been fribbling?
must you not have been fribbling?
must they not have been fribbling?