I can write you can write he can write we can write you can write they can write
V-ing form
I can be writing you can be writing he can be writing we can be writing you can be writing they can be writing
Perfect
I can have written you can have written he can have written we can have written you can have written they can have written
V-ing perfect
I can have been writing you can have been writing he can have been writing we can have been writing you can have been writing they can have been writing
Negation
Simple form
I can't write you can't write he can't write we can't write you can't write they can't write
V-ing form
I can't be writing you can't be writing he can't be writing we can't be writing you can't be writing they can't be writing
Perfect
I can't have written you can't have written he can't have written we can't have written you can't have written they can't have written
V-ing perfect
I can't have been writing you can't have been writing he can't have been writing we can't have been writing you can't have been writing they can't have been writing
Interrogative form
Simple form
can I write? can you write? can he write? can we write? can you write? can they write?
V-ing form
can I be writing? can you be writing? can he be writing? can we be writing? can you be writing? can they be writing?
Perfect
can I have written? can you have written? can he have written? can we have written? can you have written? can they have written?
V-ing perfect
can I have been writing? can you have been writing? can he have been writing? can we have been writing? can you have been writing? can they have been writing?
Interro-negative form
Simple form
can't I write? can't you write? can't he write? can't we write? can't you write? can't they write?
V-ing form
can't I be writing? can't you be writing? can't he be writing? can't we be writing? can't you be writing? can't they be writing?
Perfect
can't I have written? can't you have written? can't he have written? can't we have written? can't you have written? can't they have written?
V-ing perfect
can't I have been writing? can't you have been writing? can't he have been writing? can't we have been writing? can't you have been writing? can't they have been writing?