must niggle
Regular verb: niggle - niggled- niggled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must niggle
you must niggle
he must niggle
we must niggle
you must niggle
they must niggle 	I must be niggling
you must be niggling
he must be niggling
we must be niggling
you must be niggling
they must be niggling	I must have niggled
you must have niggled
he must have niggled
we must have niggled
you must have niggled
they must have niggled	I must have been niggling
you must have been niggling
he must have been niggling
we must have been niggling
you must have been niggling
they must have been niggling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't niggle
you mustn't niggle
he mustn't niggle
we mustn't niggle
you mustn't niggle
they mustn't niggle 	I mustn't be niggling
you mustn't be niggling
he mustn't be niggling
we mustn't be niggling
you mustn't be niggling
they mustn't be niggling	I mustn't have niggled
you mustn't have niggled
he mustn't have niggled
we mustn't have niggled
you mustn't have niggled
they mustn't have niggled	I mustn't have been niggling
you mustn't have been niggling
he mustn't have been niggling
we mustn't have been niggling
you mustn't have been niggling
they mustn't have been niggling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I niggle?
must you niggle?
must he niggle?
must we niggle?
must you niggle?
must they niggle? 	must I be niggling?
must you be niggling?
must he be niggling?
must we be niggling?
must you be niggling?
must they be niggling? 	must I have niggled?
must you have niggled?
must he have niggled?
must we have niggled?
must you have niggled?
must they have niggled? 	must I have been niggling?
must you have been niggling?
must he have been niggling?
must we have been niggling?
must you have been niggling?
must they have been niggling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I niggle?
mustn't you niggle?
mustn't he niggle?
mustn't we niggle?
mustn't you niggle?
mustn't they niggle? 	mustn't I be niggling?
mustn't you be niggling?
mustn't he be niggling?
mustn't we be niggling?
mustn't you be niggling?
mustn't they be niggling? 	mustn't I have niggled?
mustn't you have niggled?
mustn't he have niggled?
mustn't we have niggled?
mustn't you have niggled?
mustn't they have niggled? 	mustn't I have been niggling?
mustn't you have been niggling?
mustn't he have been niggling?
mustn't we have been niggling?
mustn't you have been niggling?
mustn't they have been niggling?