I can allow you can allow he can allow we can allow you can allow they can allow
V-ing form
I can be allowing you can be allowing he can be allowing we can be allowing you can be allowing they can be allowing
Perfect
I can have allowed you can have allowed he can have allowed we can have allowed you can have allowed they can have allowed
V-ing perfect
I can have been allowing you can have been allowing he can have been allowing we can have been allowing you can have been allowing they can have been allowing
Negation
Simple form
I can't allow you can't allow he can't allow we can't allow you can't allow they can't allow
V-ing form
I can't be allowing you can't be allowing he can't be allowing we can't be allowing you can't be allowing they can't be allowing
Perfect
I can't have allowed you can't have allowed he can't have allowed we can't have allowed you can't have allowed they can't have allowed
V-ing perfect
I can't have been allowing you can't have been allowing he can't have been allowing we can't have been allowing you can't have been allowing they can't have been allowing
Interrogative form
Simple form
can I allow? can you allow? can he allow? can we allow? can you allow? can they allow?
V-ing form
can I be allowing? can you be allowing? can he be allowing? can we be allowing? can you be allowing? can they be allowing?
Perfect
can I have allowed? can you have allowed? can he have allowed? can we have allowed? can you have allowed? can they have allowed?
V-ing perfect
can I have been allowing? can you have been allowing? can he have been allowing? can we have been allowing? can you have been allowing? can they have been allowing?
Interro-negative form
Simple form
can't I allow? can't you allow? can't he allow? can't we allow? can't you allow? can't they allow?
V-ing form
can't I be allowing? can't you be allowing? can't he be allowing? can't we be allowing? can't you be allowing? can't they be allowing?
Perfect
can't I have allowed? can't you have allowed? can't he have allowed? can't we have allowed? can't you have allowed? can't they have allowed?
V-ing perfect
can't I have been allowing? can't you have been allowing? can't he have been allowing? can't we have been allowing? can't you have been allowing? can't they have been allowing?