I can fold you can fold she can fold we can fold you can fold they can fold
V-ing form
I can be folding you can be folding she can be folding we can be folding you can be folding they can be folding
Perfect
I can have folded you can have folded she 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 she can have been folding we can have been folding you can have been folding they can have been folding
Negation
Simple form
I cannot fold you cannot fold she cannot fold we cannot fold you cannot fold they cannot fold
V-ing form
I cannot be folding you cannot be folding she cannot be folding we cannot be folding you cannot be folding they cannot be folding
Perfect
I cannot have folded you cannot have folded she cannot have folded we cannot have folded you cannot have folded they cannot have folded
V-ing perfect
I cannot have been folding you cannot have been folding she cannot have been folding we cannot have been folding you cannot have been folding they cannot have been folding
Interrogative form
Simple form
can I fold? can you fold? can she fold? can we fold? can you fold? can they fold?
V-ing form
can I be folding? can you be folding? can she be folding? can we be folding? can you be folding? can they be folding?
Perfect
can I have folded? can you have folded? can she 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 she have been folding? can we have been folding? can you have been folding? can they have been folding?
Interro-negative form
Simple form
can I not fold? can you not fold? can she not fold? can we not fold? can you not fold? can they not fold?
V-ing form
can I not be folding? can you not be folding? can she not be folding? can we not be folding? can you not be folding? can they not be folding?
Perfect
can I not have folded? can you not have folded? can she not have folded? can we not have folded? can you not have folded? can they not have folded?
V-ing perfect
can I not have been folding? can you not have been folding? can she not have been folding? can we not have been folding? can you not have been folding? can they not have been folding?