English verb conjugation
COULD JOIN

Regular verb: join - joined - joined

Affirmation

Simple form	V-ing form
I could join you could join he could join we could join you could join they could join	I could be joining you could be joining he could be joining we could be joining you could be joining they could be joining
Perfect	V-ing perfect
I could have joined you could have joined he could have joined we could have joined you could have joined they could have joined	I could have been joining you could have been joining he could have been joining we could have been joining you could have been joining they could have been joining

Negation

Simple form	V-ing form
I could not join you could not join he could not join we could not join you could not join they could not join	I could not be joining you could not be joining he could not be joining we could not be joining you could not be joining they could not be joining
Perfect	V-ing perfect
I could not have joined you could not have joined he could not have joined we could not have joined you could not have joined they could not have joined	I could not have been joining you could not have been joining he could not have been joining we could not have been joining you could not have been joining they could not have been joining

Interrogative form

Simple form	V-ing form
could I join? could you join? could he join? could we join? could you join? could they join?	could I be joining? could you be joining? could he be joining? could we be joining? could you be joining? could they be joining?
Perfect	V-ing perfect
could I have joined? could you have joined? could he have joined? could we have joined? could you have joined? could they have joined?	could I have been joining? could you have been joining? could he have been joining? could we have been joining? could you have been joining? could they have been joining?

Interro-negative form

Simple form	V-ing form
could I not join? could you not join? could he not join? could we not join? could you not join? could they not join?	could I not be joining? could you not be joining? could he not be joining? could we not be joining? could you not be joining? could they not be joining?
Perfect	V-ing perfect
could I not have joined? could you not have joined? could he not have joined? could we not have joined? could you not have joined? could they not have joined?	could I not have been joining? could you not have been joining? could he not have been joining? could we not have been joining? could you not have been joining? could they not have been joining?