English verb conjugation
COULD NIGGLE

Regular verb: niggle - niggled - niggled

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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