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 must not niggle you must not niggle he must not niggle we must not niggle you must not niggle they must not niggle	I must not be niggling you must not be niggling he must not be niggling we must not be niggling you must not be niggling they must not be niggling
Perfect	V-ing perfect
I must not have niggled you must not have niggled he must not have niggled we must not have niggled you must not have niggled they must not have niggled	I must not have been niggling you must not have been niggling he must not have been niggling we must not have been niggling you must not have been niggling they must not 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
must I not niggle? must you not niggle? must he not niggle? must we not niggle? must you not niggle? must they not niggle?	must I not be niggling? must you not be niggling? must he not be niggling? must we not be niggling? must you not be niggling? must they not be niggling?
Perfect	V-ing perfect
must I not have niggled? must you not have niggled? must he not have niggled? must we not have niggled? must you not have niggled? must they not have niggled?	must I not have been niggling? must you not have been niggling? must he not have been niggling? must we not have been niggling? must you not have been niggling? must they not have been niggling?