I could visit you could visit she could visit we could visit you could visit they could visit
V-ing form
I could be visiting you could be visiting she could be visiting we could be visiting you could be visiting they could be visiting
Perfect
I could have visited you could have visited she could have visited we could have visited you could have visited they could have visited
V-ing perfect
I could have been visiting you could have been visiting she could have been visiting we could have been visiting you could have been visiting they could have been visiting
Negation
Simple form
I could not visit you could not visit she could not visit we could not visit you could not visit they could not visit
V-ing form
I could not be visiting you could not be visiting she could not be visiting we could not be visiting you could not be visiting they could not be visiting
Perfect
I could not have visited you could not have visited she could not have visited we could not have visited you could not have visited they could not have visited
V-ing perfect
I could not have been visiting you could not have been visiting she could not have been visiting we could not have been visiting you could not have been visiting they could not have been visiting
Interrogative form
Simple form
could I visit? could you visit? could she visit? could we visit? could you visit? could they visit?
V-ing form
could I be visiting? could you be visiting? could she be visiting? could we be visiting? could you be visiting? could they be visiting?
Perfect
could I have visited? could you have visited? could she have visited? could we have visited? could you have visited? could they have visited?
V-ing perfect
could I have been visiting? could you have been visiting? could she have been visiting? could we have been visiting? could you have been visiting? could they have been visiting?
Interro-negative form
Simple form
could I not visit? could you not visit? could she not visit? could we not visit? could you not visit? could they not visit?
V-ing form
could I not be visiting? could you not be visiting? could she not be visiting? could we not be visiting? could you not be visiting? could they not be visiting?
Perfect
could I not have visited? could you not have visited? could she not have visited? could we not have visited? could you not have visited? could they not have visited?
V-ing perfect
could I not have been visiting? could you not have been visiting? could she not have been visiting? could we not have been visiting? could you not have been visiting? could they not have been visiting?