I could varnish you could varnish he could varnish we could varnish you could varnish they could varnish
V-ing form
I could be varnishing you could be varnishing he could be varnishing we could be varnishing you could be varnishing they could be varnishing
Perfect
I could have varnished you could have varnished he could have varnished we could have varnished you could have varnished they could have varnished
V-ing perfect
I could have been varnishing you could have been varnishing he could have been varnishing we could have been varnishing you could have been varnishing they could have been varnishing
Negation
Simple form
I could not varnish you could not varnish he could not varnish we could not varnish you could not varnish they could not varnish
V-ing form
I could not be varnishing you could not be varnishing he could not be varnishing we could not be varnishing you could not be varnishing they could not be varnishing
Perfect
I could not have varnished you could not have varnished he could not have varnished we could not have varnished you could not have varnished they could not have varnished
V-ing perfect
I could not have been varnishing you could not have been varnishing he could not have been varnishing we could not have been varnishing you could not have been varnishing they could not have been varnishing
Interrogative form
Simple form
could I varnish? could you varnish? could he varnish? could we varnish? could you varnish? could they varnish?
V-ing form
could I be varnishing? could you be varnishing? could he be varnishing? could we be varnishing? could you be varnishing? could they be varnishing?
Perfect
could I have varnished? could you have varnished? could he have varnished? could we have varnished? could you have varnished? could they have varnished?
V-ing perfect
could I have been varnishing? could you have been varnishing? could he have been varnishing? could we have been varnishing? could you have been varnishing? could they have been varnishing?
Interro-negative form
Simple form
could I not varnish? could you not varnish? could he not varnish? could we not varnish? could you not varnish? could they not varnish?
V-ing form
could I not be varnishing? could you not be varnishing? could he not be varnishing? could we not be varnishing? could you not be varnishing? could they not be varnishing?
Perfect
could I not have varnished? could you not have varnished? could he not have varnished? could we not have varnished? could you not have varnished? could they not have varnished?
V-ing perfect
could I not have been varnishing? could you not have been varnishing? could he not have been varnishing? could we not have been varnishing? could you not have been varnishing? could they not have been varnishing?