English verb conjugation
COULD RETURN

Regular verb: return - returned - returned

Affirmation

Simple form	V-ing form
I could return you could return he could return we could return you could return they could return	I could be returning you could be returning he could be returning we could be returning you could be returning they could be returning
Perfect	V-ing perfect
I could have returned you could have returned he could have returned we could have returned you could have returned they could have returned	I could have been returning you could have been returning he could have been returning we could have been returning you could have been returning they could have been returning

Negation

Simple form	V-ing form
I couldn't return you couldn't return he couldn't return we couldn't return you couldn't return they couldn't return	I couldn't be returning you couldn't be returning he couldn't be returning we couldn't be returning you couldn't be returning they couldn't be returning
Perfect	V-ing perfect
I couldn't have returned you couldn't have returned he couldn't have returned we couldn't have returned you couldn't have returned they couldn't have returned	I couldn't have been returning you couldn't have been returning he couldn't have been returning we couldn't have been returning you couldn't have been returning they couldn't have been returning

Interrogative form

Simple form	V-ing form
could I return? could you return? could he return? could we return? could you return? could they return?	could I be returning? could you be returning? could he be returning? could we be returning? could you be returning? could they be returning?
Perfect	V-ing perfect
could I have returned? could you have returned? could he have returned? could we have returned? could you have returned? could they have returned?	could I have been returning? could you have been returning? could he have been returning? could we have been returning? could you have been returning? could they have been returning?

Interro-negative form

Simple form	V-ing form
couldn't I return? couldn't you return? couldn't he return? couldn't we return? couldn't you return? couldn't they return?	couldn't I be returning? couldn't you be returning? couldn't he be returning? couldn't we be returning? couldn't you be returning? couldn't they be returning?
Perfect	V-ing perfect
couldn't I have returned? couldn't you have returned? couldn't he have returned? couldn't we have returned? couldn't you have returned? couldn't they have returned?	couldn't I have been returning? couldn't you have been returning? couldn't he have been returning? couldn't we have been returning? couldn't you have been returning? couldn't they have been returning?