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