English verb conjugation
MUST NIGGLE

Regular verb: niggle - niggled - niggled

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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
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
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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?