I can attach you can attach he can attach we can attach you can attach they can attach
V-ing form
I can be attaching you can be attaching he can be attaching we can be attaching you can be attaching they can be attaching
Perfect
I can have attached you can have attached he can have attached we can have attached you can have attached they can have attached
V-ing perfect
I can have been attaching you can have been attaching he can have been attaching we can have been attaching you can have been attaching they can have been attaching
Negation
Simple form
I can't attach you can't attach he can't attach we can't attach you can't attach they can't attach
V-ing form
I can't be attaching you can't be attaching he can't be attaching we can't be attaching you can't be attaching they can't be attaching
Perfect
I can't have attached you can't have attached he can't have attached we can't have attached you can't have attached they can't have attached
V-ing perfect
I can't have been attaching you can't have been attaching he can't have been attaching we can't have been attaching you can't have been attaching they can't have been attaching
Interrogative form
Simple form
can I attach? can you attach? can he attach? can we attach? can you attach? can they attach?
V-ing form
can I be attaching? can you be attaching? can he be attaching? can we be attaching? can you be attaching? can they be attaching?
Perfect
can I have attached? can you have attached? can he have attached? can we have attached? can you have attached? can they have attached?
V-ing perfect
can I have been attaching? can you have been attaching? can he have been attaching? can we have been attaching? can you have been attaching? can they have been attaching?
Interro-negative form
Simple form
can't I attach? can't you attach? can't he attach? can't we attach? can't you attach? can't they attach?
V-ing form
can't I be attaching? can't you be attaching? can't he be attaching? can't we be attaching? can't you be attaching? can't they be attaching?
Perfect
can't I have attached? can't you have attached? can't he have attached? can't we have attached? can't you have attached? can't they have attached?
V-ing perfect
can't I have been attaching? can't you have been attaching? can't he have been attaching? can't we have been attaching? can't you have been attaching? can't they have been attaching?