I could pump you could pump she could pump we could pump you could pump they could pump
V-ing form
I could be pumping you could be pumping she could be pumping we could be pumping you could be pumping they could be pumping
Perfect
I could have pumped you could have pumped she could have pumped we could have pumped you could have pumped they could have pumped
V-ing perfect
I could have been pumping you could have been pumping she could have been pumping we could have been pumping you could have been pumping they could have been pumping
Negation
Simple form
I could not pump you could not pump she could not pump we could not pump you could not pump they could not pump
V-ing form
I could not be pumping you could not be pumping she could not be pumping we could not be pumping you could not be pumping they could not be pumping
Perfect
I could not have pumped you could not have pumped she could not have pumped we could not have pumped you could not have pumped they could not have pumped
V-ing perfect
I could not have been pumping you could not have been pumping she could not have been pumping we could not have been pumping you could not have been pumping they could not have been pumping
Interrogative form
Simple form
could I pump? could you pump? could she pump? could we pump? could you pump? could they pump?
V-ing form
could I be pumping? could you be pumping? could she be pumping? could we be pumping? could you be pumping? could they be pumping?
Perfect
could I have pumped? could you have pumped? could she have pumped? could we have pumped? could you have pumped? could they have pumped?
V-ing perfect
could I have been pumping? could you have been pumping? could she have been pumping? could we have been pumping? could you have been pumping? could they have been pumping?
Interro-negative form
Simple form
could I not pump? could you not pump? could she not pump? could we not pump? could you not pump? could they not pump?
V-ing form
could I not be pumping? could you not be pumping? could she not be pumping? could we not be pumping? could you not be pumping? could they not be pumping?
Perfect
could I not have pumped? could you not have pumped? could she not have pumped? could we not have pumped? could you not have pumped? could they not have pumped?
V-ing perfect
could I not have been pumping? could you not have been pumping? could she not have been pumping? could we not have been pumping? could you not have been pumping? could they not have been pumping?