I can fire you can fire she can fire we can fire you can fire they can fire
V-ing form
I can be firing you can be firing she can be firing we can be firing you can be firing they can be firing
Perfect
I can have fired you can have fired she can have fired we can have fired you can have fired they can have fired
V-ing perfect
I can have been firing you can have been firing she can have been firing we can have been firing you can have been firing they can have been firing
Negation
Simple form
I can't fire you can't fire she can't fire we can't fire you can't fire they can't fire
V-ing form
I can't be firing you can't be firing she can't be firing we can't be firing you can't be firing they can't be firing
Perfect
I can't have fired you can't have fired she can't have fired we can't have fired you can't have fired they can't have fired
V-ing perfect
I can't have been firing you can't have been firing she can't have been firing we can't have been firing you can't have been firing they can't have been firing
Interrogative form
Simple form
can I fire? can you fire? can she fire? can we fire? can you fire? can they fire?
V-ing form
can I be firing? can you be firing? can she be firing? can we be firing? can you be firing? can they be firing?
Perfect
can I have fired? can you have fired? can she have fired? can we have fired? can you have fired? can they have fired?
V-ing perfect
can I have been firing? can you have been firing? can she have been firing? can we have been firing? can you have been firing? can they have been firing?
Interro-negative form
Simple form
can't I fire? can't you fire? can't she fire? can't we fire? can't you fire? can't they fire?
V-ing form
can't I be firing? can't you be firing? can't she be firing? can't we be firing? can't you be firing? can't they be firing?
Perfect
can't I have fired? can't you have fired? can't she have fired? can't we have fired? can't you have fired? can't they have fired?
V-ing perfect
can't I have been firing? can't you have been firing? can't she have been firing? can't we have been firing? can't you have been firing? can't they have been firing?