English verb conjugation
COULD RIFFLE

Regular verb: riffle - riffled - riffled

Affirmation

Simple form	V-ing form
I could riffle you could riffle she could riffle we could riffle you could riffle they could riffle	I could be riffling you could be riffling she 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 she 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 she 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 couldn't riffle you couldn't riffle she couldn't riffle we couldn't riffle you couldn't riffle they couldn't riffle	I couldn't be riffling you couldn't be riffling she couldn't be riffling we couldn't be riffling you couldn't be riffling they couldn't be riffling
Perfect	V-ing perfect
I couldn't have riffled you couldn't have riffled she couldn't have riffled we couldn't have riffled you couldn't have riffled they couldn't have riffled	I couldn't have been riffling you couldn't have been riffling she couldn't have been riffling we couldn't have been riffling you couldn't have been riffling they couldn't have been riffling

Interrogative form

Simple form	V-ing form
could I riffle? could you riffle? could she riffle? could we riffle? could you riffle? could they riffle?	could I be riffling? could you be riffling? could she 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 she 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 she 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
couldn't I riffle? couldn't you riffle? couldn't she riffle? couldn't we riffle? couldn't you riffle? couldn't they riffle?	couldn't I be riffling? couldn't you be riffling? couldn't she be riffling? couldn't we be riffling? couldn't you be riffling? couldn't they be riffling?
Perfect	V-ing perfect
couldn't I have riffled? couldn't you have riffled? couldn't she have riffled? couldn't we have riffled? couldn't you have riffled? couldn't they have riffled?	couldn't I have been riffling? couldn't you have been riffling? couldn't she have been riffling? couldn't we have been riffling? couldn't you have been riffling? couldn't they have been riffling?