could niggle
Regular verb: niggle - niggled- niggled

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