I could chap you could chap she could chap we could chap you could chap they could chap
V-ing form
I could be chapping you could be chapping she could be chapping we could be chapping you could be chapping they could be chapping
Perfect
I could have chapped you could have chapped she could have chapped we could have chapped you could have chapped they could have chapped
V-ing perfect
I could have been chapping you could have been chapping she could have been chapping we could have been chapping you could have been chapping they could have been chapping
Negation
Simple form
I could not chap you could not chap she could not chap we could not chap you could not chap they could not chap
V-ing form
I could not be chapping you could not be chapping she could not be chapping we could not be chapping you could not be chapping they could not be chapping
Perfect
I could not have chapped you could not have chapped she could not have chapped we could not have chapped you could not have chapped they could not have chapped
V-ing perfect
I could not have been chapping you could not have been chapping she could not have been chapping we could not have been chapping you could not have been chapping they could not have been chapping
Interrogative form
Simple form
could I chap? could you chap? could she chap? could we chap? could you chap? could they chap?
V-ing form
could I be chapping? could you be chapping? could she be chapping? could we be chapping? could you be chapping? could they be chapping?
Perfect
could I have chapped? could you have chapped? could she have chapped? could we have chapped? could you have chapped? could they have chapped?
V-ing perfect
could I have been chapping? could you have been chapping? could she have been chapping? could we have been chapping? could you have been chapping? could they have been chapping?
Interro-negative form
Simple form
could I not chap? could you not chap? could she not chap? could we not chap? could you not chap? could they not chap?
V-ing form
could I not be chapping? could you not be chapping? could she not be chapping? could we not be chapping? could you not be chapping? could they not be chapping?
Perfect
could I not have chapped? could you not have chapped? could she not have chapped? could we not have chapped? could you not have chapped? could they not have chapped?
V-ing perfect
could I not have been chapping? could you not have been chapping? could she not have been chapping? could we not have been chapping? could you not have been chapping? could they not have been chapping?