I could datestamp you could datestamp he could datestamp we could datestamp you could datestamp they could datestamp
V-ing form
I could be datestamping you could be datestamping he could be datestamping we could be datestamping you could be datestamping they could be datestamping
Perfect
I could have datestamped you could have datestamped he could have datestamped we could have datestamped you could have datestamped they could have datestamped
V-ing perfect
I could have been datestamping you could have been datestamping he could have been datestamping we could have been datestamping you could have been datestamping they could have been datestamping
Negation
Simple form
I could not datestamp you could not datestamp he could not datestamp we could not datestamp you could not datestamp they could not datestamp
V-ing form
I could not be datestamping you could not be datestamping he could not be datestamping we could not be datestamping you could not be datestamping they could not be datestamping
Perfect
I could not have datestamped you could not have datestamped he could not have datestamped we could not have datestamped you could not have datestamped they could not have datestamped
V-ing perfect
I could not have been datestamping you could not have been datestamping he could not have been datestamping we could not have been datestamping you could not have been datestamping they could not have been datestamping
Interrogative form
Simple form
could I datestamp? could you datestamp? could he datestamp? could we datestamp? could you datestamp? could they datestamp?
V-ing form
could I be datestamping? could you be datestamping? could he be datestamping? could we be datestamping? could you be datestamping? could they be datestamping?
Perfect
could I have datestamped? could you have datestamped? could he have datestamped? could we have datestamped? could you have datestamped? could they have datestamped?
V-ing perfect
could I have been datestamping? could you have been datestamping? could he have been datestamping? could we have been datestamping? could you have been datestamping? could they have been datestamping?
Interro-negative form
Simple form
could I not datestamp? could you not datestamp? could he not datestamp? could we not datestamp? could you not datestamp? could they not datestamp?
V-ing form
could I not be datestamping? could you not be datestamping? could he not be datestamping? could we not be datestamping? could you not be datestamping? could they not be datestamping?
Perfect
could I not have datestamped? could you not have datestamped? could he not have datestamped? could we not have datestamped? could you not have datestamped? could they not have datestamped?
V-ing perfect
could I not have been datestamping? could you not have been datestamping? could he not have been datestamping? could we not have been datestamping? could you not have been datestamping? could they not have been datestamping?