I could hem you could hem she could hem we could hem you could hem they could hem
V-ing form
I could be hemming you could be hemming she could be hemming we could be hemming you could be hemming they could be hemming
Perfect
I could have hemmed you could have hemmed she could have hemmed we could have hemmed you could have hemmed they could have hemmed
V-ing perfect
I could have been hemming you could have been hemming she could have been hemming we could have been hemming you could have been hemming they could have been hemming
Negation
Simple form
I could not hem you could not hem she could not hem we could not hem you could not hem they could not hem
V-ing form
I could not be hemming you could not be hemming she could not be hemming we could not be hemming you could not be hemming they could not be hemming
Perfect
I could not have hemmed you could not have hemmed she could not have hemmed we could not have hemmed you could not have hemmed they could not have hemmed
V-ing perfect
I could not have been hemming you could not have been hemming she could not have been hemming we could not have been hemming you could not have been hemming they could not have been hemming
Interrogative form
Simple form
could I hem? could you hem? could she hem? could we hem? could you hem? could they hem?
V-ing form
could I be hemming? could you be hemming? could she be hemming? could we be hemming? could you be hemming? could they be hemming?
Perfect
could I have hemmed? could you have hemmed? could she have hemmed? could we have hemmed? could you have hemmed? could they have hemmed?
V-ing perfect
could I have been hemming? could you have been hemming? could she have been hemming? could we have been hemming? could you have been hemming? could they have been hemming?
Interro-negative form
Simple form
could I not hem? could you not hem? could she not hem? could we not hem? could you not hem? could they not hem?
V-ing form
could I not be hemming? could you not be hemming? could she not be hemming? could we not be hemming? could you not be hemming? could they not be hemming?
Perfect
could I not have hemmed? could you not have hemmed? could she not have hemmed? could we not have hemmed? could you not have hemmed? could they not have hemmed?
V-ing perfect
could I not have been hemming? could you not have been hemming? could she not have been hemming? could we not have been hemming? could you not have been hemming? could they not have been hemming?