I could correspond you could correspond she could correspond we could correspond you could correspond they could correspond
V-ing form
I could be corresponding you could be corresponding she could be corresponding we could be corresponding you could be corresponding they could be corresponding
Perfect
I could have corresponded you could have corresponded she could have corresponded we could have corresponded you could have corresponded they could have corresponded
V-ing perfect
I could have been corresponding you could have been corresponding she could have been corresponding we could have been corresponding you could have been corresponding they could have been corresponding
Negation
Simple form
I could not correspond you could not correspond she could not correspond we could not correspond you could not correspond they could not correspond
V-ing form
I could not be corresponding you could not be corresponding she could not be corresponding we could not be corresponding you could not be corresponding they could not be corresponding
Perfect
I could not have corresponded you could not have corresponded she could not have corresponded we could not have corresponded you could not have corresponded they could not have corresponded
V-ing perfect
I could not have been corresponding you could not have been corresponding she could not have been corresponding we could not have been corresponding you could not have been corresponding they could not have been corresponding
Interrogative form
Simple form
could I correspond? could you correspond? could she correspond? could we correspond? could you correspond? could they correspond?
V-ing form
could I be corresponding? could you be corresponding? could she be corresponding? could we be corresponding? could you be corresponding? could they be corresponding?
Perfect
could I have corresponded? could you have corresponded? could she have corresponded? could we have corresponded? could you have corresponded? could they have corresponded?
V-ing perfect
could I have been corresponding? could you have been corresponding? could she have been corresponding? could we have been corresponding? could you have been corresponding? could they have been corresponding?
Interro-negative form
Simple form
could I not correspond? could you not correspond? could she not correspond? could we not correspond? could you not correspond? could they not correspond?
V-ing form
could I not be corresponding? could you not be corresponding? could she not be corresponding? could we not be corresponding? could you not be corresponding? could they not be corresponding?
Perfect
could I not have corresponded? could you not have corresponded? could she not have corresponded? could we not have corresponded? could you not have corresponded? could they not have corresponded?
V-ing perfect
could I not have been corresponding? could you not have been corresponding? could she not have been corresponding? could we not have been corresponding? could you not have been corresponding? could they not have been corresponding?