English verb conjugation
COULD RIFFLE

Regular verb: riffle - riffled - riffled

Affirmation

Simple form	V-ing form
I could riffle you could riffle he could riffle we could riffle you could riffle they could riffle	I could be riffling you could be riffling he could be riffling we could be riffling you could be riffling they could be riffling
Perfect	V-ing perfect
I could have riffled you could have riffled he could have riffled we could have riffled you could have riffled they could have riffled	I could have been riffling you could have been riffling he could have been riffling we could have been riffling you could have been riffling they could have been riffling

Negation

Simple form	V-ing form
I could not riffle you could not riffle he could not riffle we could not riffle you could not riffle they could not riffle	I could not be riffling you could not be riffling he could not be riffling we could not be riffling you could not be riffling they could not be riffling
Perfect	V-ing perfect
I could not have riffled you could not have riffled he could not have riffled we could not have riffled you could not have riffled they could not have riffled	I could not have been riffling you could not have been riffling he could not have been riffling we could not have been riffling you could not have been riffling they could not have been riffling

Interrogative form

Simple form	V-ing form
could I riffle? could you riffle? could he riffle? could we riffle? could you riffle? could they riffle?	could I be riffling? could you be riffling? could he be riffling? could we be riffling? could you be riffling? could they be riffling?
Perfect	V-ing perfect
could I have riffled? could you have riffled? could he have riffled? could we have riffled? could you have riffled? could they have riffled?	could I have been riffling? could you have been riffling? could he have been riffling? could we have been riffling? could you have been riffling? could they have been riffling?

Interro-negative form

Simple form	V-ing form
could I not riffle? could you not riffle? could he not riffle? could we not riffle? could you not riffle? could they not riffle?	could I not be riffling? could you not be riffling? could he not be riffling? could we not be riffling? could you not be riffling? could they not be riffling?
Perfect	V-ing perfect
could I not have riffled? could you not have riffled? could he not have riffled? could we not have riffled? could you not have riffled? could they not have riffled?	could I not have been riffling? could you not have been riffling? could he not have been riffling? could we not have been riffling? could you not have been riffling? could they not have been riffling?