could join
Regular verb: join - joined- joined

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