English verb conjugation
COULD KNUCKLE

Regular verb: knuckle - knuckled - knuckled

Affirmation

Simple form	V-ing form
I could knuckle you could knuckle he could knuckle we could knuckle you could knuckle they could knuckle	I could be knuckling you could be knuckling he could be knuckling we could be knuckling you could be knuckling they could be knuckling
Perfect	V-ing perfect
I could have knuckled you could have knuckled he could have knuckled we could have knuckled you could have knuckled they could have knuckled	I could have been knuckling you could have been knuckling he could have been knuckling we could have been knuckling you could have been knuckling they could have been knuckling

Negation

Simple form	V-ing form
I couldn't knuckle you couldn't knuckle he couldn't knuckle we couldn't knuckle you couldn't knuckle they couldn't knuckle	I couldn't be knuckling you couldn't be knuckling he couldn't be knuckling we couldn't be knuckling you couldn't be knuckling they couldn't be knuckling
Perfect	V-ing perfect
I couldn't have knuckled you couldn't have knuckled he couldn't have knuckled we couldn't have knuckled you couldn't have knuckled they couldn't have knuckled	I couldn't have been knuckling you couldn't have been knuckling he couldn't have been knuckling we couldn't have been knuckling you couldn't have been knuckling they couldn't have been knuckling

Interrogative form

Simple form	V-ing form
could I knuckle? could you knuckle? could he knuckle? could we knuckle? could you knuckle? could they knuckle?	could I be knuckling? could you be knuckling? could he be knuckling? could we be knuckling? could you be knuckling? could they be knuckling?
Perfect	V-ing perfect
could I have knuckled? could you have knuckled? could he have knuckled? could we have knuckled? could you have knuckled? could they have knuckled?	could I have been knuckling? could you have been knuckling? could he have been knuckling? could we have been knuckling? could you have been knuckling? could they have been knuckling?

Interro-negative form

Simple form	V-ing form
couldn't I knuckle? couldn't you knuckle? couldn't he knuckle? couldn't we knuckle? couldn't you knuckle? couldn't they knuckle?	couldn't I be knuckling? couldn't you be knuckling? couldn't he be knuckling? couldn't we be knuckling? couldn't you be knuckling? couldn't they be knuckling?
Perfect	V-ing perfect
couldn't I have knuckled? couldn't you have knuckled? couldn't he have knuckled? couldn't we have knuckled? couldn't you have knuckled? couldn't they have knuckled?	couldn't I have been knuckling? couldn't you have been knuckling? couldn't he have been knuckling? couldn't we have been knuckling? couldn't you have been knuckling? couldn't they have been knuckling?