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 couldn't nod you couldn't nod he couldn't nod we couldn't nod you couldn't nod they couldn't nod	I couldn't be nodding you couldn't be nodding he couldn't be nodding we couldn't be nodding you couldn't be nodding they couldn't be nodding
Perfect	V-ing perfect
I couldn't have nodded you couldn't have nodded he couldn't have nodded we couldn't have nodded you couldn't have nodded they couldn't have nodded	I couldn't have been nodding you couldn't have been nodding he couldn't have been nodding we couldn't have been nodding you couldn't have been nodding they couldn't 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
couldn't I nod? couldn't you nod? couldn't he nod? couldn't we nod? couldn't you nod? couldn't they nod?	couldn't I be nodding? couldn't you be nodding? couldn't he be nodding? couldn't we be nodding? couldn't you be nodding? couldn't they be nodding?
Perfect	V-ing perfect
couldn't I have nodded? couldn't you have nodded? couldn't he have nodded? couldn't we have nodded? couldn't you have nodded? couldn't they have nodded?	couldn't I have been nodding? couldn't you have been nodding? couldn't he have been nodding? couldn't we have been nodding? couldn't you have been nodding? couldn't they have been nodding?