must fribble
Regular verb: fribble - fribbled- fribbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must fribble
you must fribble
he must fribble
we must fribble
you must fribble
they must fribble 	I must be fribbling
you must be fribbling
he must be fribbling
we must be fribbling
you must be fribbling
they must be fribbling	I must have fribbled
you must have fribbled
he 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
he 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 mustn't fribble
you mustn't fribble
he mustn't fribble
we mustn't fribble
you mustn't fribble
they mustn't fribble 	I mustn't be fribbling
you mustn't be fribbling
he mustn't be fribbling
we mustn't be fribbling
you mustn't be fribbling
they mustn't be fribbling	I mustn't have fribbled
you mustn't have fribbled
he mustn't have fribbled
we mustn't have fribbled
you mustn't have fribbled
they mustn't have fribbled	I mustn't have been fribbling
you mustn't have been fribbling
he mustn't have been fribbling
we mustn't have been fribbling
you mustn't have been fribbling
they mustn't have been fribbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I fribble?
must you fribble?
must he fribble?
must we fribble?
must you fribble?
must they fribble? 	must I be fribbling?
must you be fribbling?
must he be fribbling?
must we be fribbling?
must you be fribbling?
must they be fribbling? 	must I have fribbled?
must you have fribbled?
must he 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 he 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 	
mustn't I fribble?
mustn't you fribble?
mustn't he fribble?
mustn't we fribble?
mustn't you fribble?
mustn't they fribble? 	mustn't I be fribbling?
mustn't you be fribbling?
mustn't he be fribbling?
mustn't we be fribbling?
mustn't you be fribbling?
mustn't they be fribbling? 	mustn't I have fribbled?
mustn't you have fribbled?
mustn't he have fribbled?
mustn't we have fribbled?
mustn't you have fribbled?
mustn't they have fribbled? 	mustn't I have been fribbling?
mustn't you have been fribbling?
mustn't he have been fribbling?
mustn't we have been fribbling?
mustn't you have been fribbling?
mustn't they have been fribbling?