I could swap you could swap she could swap we could swap you could swap they could swap
V-ing form
I could be swaping you could be swaping she could be swaping we could be swaping you could be swaping they could be swaping
Perfect
I could have swaped you could have swaped she could have swaped we could have swaped you could have swaped they could have swaped
V-ing perfect
I could have been swaping you could have been swaping she could have been swaping we could have been swaping you could have been swaping they could have been swaping
Negation
Simple form
I could not swap you could not swap she could not swap we could not swap you could not swap they could not swap
V-ing form
I could not be swaping you could not be swaping she could not be swaping we could not be swaping you could not be swaping they could not be swaping
Perfect
I could not have swaped you could not have swaped she could not have swaped we could not have swaped you could not have swaped they could not have swaped
V-ing perfect
I could not have been swaping you could not have been swaping she could not have been swaping we could not have been swaping you could not have been swaping they could not have been swaping
Interrogative form
Simple form
could I swap? could you swap? could she swap? could we swap? could you swap? could they swap?
V-ing form
could I be swaping? could you be swaping? could she be swaping? could we be swaping? could you be swaping? could they be swaping?
Perfect
could I have swaped? could you have swaped? could she have swaped? could we have swaped? could you have swaped? could they have swaped?
V-ing perfect
could I have been swaping? could you have been swaping? could she have been swaping? could we have been swaping? could you have been swaping? could they have been swaping?
Interro-negative form
Simple form
could I not swap? could you not swap? could she not swap? could we not swap? could you not swap? could they not swap?
V-ing form
could I not be swaping? could you not be swaping? could she not be swaping? could we not be swaping? could you not be swaping? could they not be swaping?
Perfect
could I not have swaped? could you not have swaped? could she not have swaped? could we not have swaped? could you not have swaped? could they not have swaped?
V-ing perfect
could I not have been swaping? could you not have been swaping? could she not have been swaping? could we not have been swaping? could you not have been swaping? could they not have been swaping?