English verb conjugation
COULD NOD

Regular verb: nod - nodded - nodded

Affirmation

Simple form	V-ing form
I could nod you could nod he could nod we could nod you could nod they could nod	I could be nodding you could be nodding he could be nodding we could be nodding you could be nodding they could be nodding
Perfect	V-ing perfect
I could have nodded you could have nodded he could have nodded we could have nodded you could have nodded they could have nodded	I could have been nodding you could have been nodding he could have been nodding we could have been nodding you could have been nodding they could have been nodding

Negation

Simple form	V-ing form
I could not nod you could not nod he could not nod we could not nod you could not nod they could not nod	I could not be nodding you could not be nodding he could not be nodding we could not be nodding you could not be nodding they could not be nodding
Perfect	V-ing perfect
I could not have nodded you could not have nodded he could not have nodded we could not have nodded you could not have nodded they could not have nodded	I could not have been nodding you could not have been nodding he could not have been nodding we could not have been nodding you could not have been nodding they could not have been nodding

Interrogative form

Simple form	V-ing form
could I nod? could you nod? could he nod? could we nod? could you nod? could they nod?	could I be nodding? could you be nodding? could he be nodding? could we be nodding? could you be nodding? could they be nodding?
Perfect	V-ing perfect
could I have nodded? could you have nodded? could he have nodded? could we have nodded? could you have nodded? could they have nodded?	could I have been nodding? could you have been nodding? could he have been nodding? could we have been nodding? could you have been nodding? could they have been nodding?

Interro-negative form

Simple form	V-ing form
could I not nod? could you not nod? could he not nod? could we not nod? could you not nod? could they not nod?	could I not be nodding? could you not be nodding? could he not be nodding? could we not be nodding? could you not be nodding? could they not be nodding?
Perfect	V-ing perfect
could I not have nodded? could you not have nodded? could he not have nodded? could we not have nodded? could you not have nodded? could they not have nodded?	could I not have been nodding? could you not have been nodding? could he not have been nodding? could we not have been nodding? could you not have been nodding? could they not have been nodding?