I can fold you can fold he can fold we can fold you can fold they can fold
V-ing form
I can be folding you can be folding he can be folding we can be folding you can be folding they can be folding
Perfect
I can have folded you can have folded he can have folded we can have folded you can have folded they can have folded
V-ing perfect
I can have been folding you can have been folding he can have been folding we can have been folding you can have been folding they can have been folding
Negation
Simple form
I can't fold you can't fold he can't fold we can't fold you can't fold they can't fold
V-ing form
I can't be folding you can't be folding he can't be folding we can't be folding you can't be folding they can't be folding
Perfect
I can't have folded you can't have folded he can't have folded we can't have folded you can't have folded they can't have folded
V-ing perfect
I can't have been folding you can't have been folding he can't have been folding we can't have been folding you can't have been folding they can't have been folding
Interrogative form
Simple form
can I fold? can you fold? can he fold? can we fold? can you fold? can they fold?
V-ing form
can I be folding? can you be folding? can he be folding? can we be folding? can you be folding? can they be folding?
Perfect
can I have folded? can you have folded? can he have folded? can we have folded? can you have folded? can they have folded?
V-ing perfect
can I have been folding? can you have been folding? can he have been folding? can we have been folding? can you have been folding? can they have been folding?
Interro-negative form
Simple form
can't I fold? can't you fold? can't he fold? can't we fold? can't you fold? can't they fold?
V-ing form
can't I be folding? can't you be folding? can't he be folding? can't we be folding? can't you be folding? can't they be folding?
Perfect
can't I have folded? can't you have folded? can't he have folded? can't we have folded? can't you have folded? can't they have folded?
V-ing perfect
can't I have been folding? can't you have been folding? can't he have been folding? can't we have been folding? can't you have been folding? can't they have been folding?