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 cannot attach you cannot attach he cannot attach we cannot attach you cannot attach they cannot attach
V-ing form
I cannot be attaching you cannot be attaching he cannot be attaching we cannot be attaching you cannot be attaching they cannot be attaching
Perfect
I cannot have attached you cannot have attached he cannot have attached we cannot have attached you cannot have attached they cannot have attached
V-ing perfect
I cannot have been attaching you cannot have been attaching he cannot have been attaching we cannot have been attaching you cannot have been attaching they cannot 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 I not attach? can you not attach? can he not attach? can we not attach? can you not attach? can they not attach?
V-ing form
can I not be attaching? can you not be attaching? can he not be attaching? can we not be attaching? can you not be attaching? can they not be attaching?
Perfect
can I not have attached? can you not have attached? can he not have attached? can we not have attached? can you not have attached? can they not have attached?
V-ing perfect
can I not have been attaching? can you not have been attaching? can he not have been attaching? can we not have been attaching? can you not have been attaching? can they not have been attaching?