Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could series you could series he could series we could series you could series they could series
V-ing form
I could be seriesing you could be seriesing he could be seriesing we could be seriesing you could be seriesing they could be seriesing
Perfect
I could have seriesed you could have seriesed he could have seriesed we could have seriesed you could have seriesed they could have seriesed
V-ing perfect
I could have been seriesing you could have been seriesing he could have been seriesing we could have been seriesing you could have been seriesing they could have been seriesing
Negation
Simple form
I could not series you could not series he could not series we could not series you could not series they could not series
V-ing form
I could not be seriesing you could not be seriesing he could not be seriesing we could not be seriesing you could not be seriesing they could not be seriesing
Perfect
I could not have seriesed you could not have seriesed he could not have seriesed we could not have seriesed you could not have seriesed they could not have seriesed
V-ing perfect
I could not have been seriesing you could not have been seriesing he could not have been seriesing we could not have been seriesing you could not have been seriesing they could not have been seriesing
Interrogative form
Simple form
could I series? could you series? could he series? could we series? could you series? could they series?
V-ing form
could I be seriesing? could you be seriesing? could he be seriesing? could we be seriesing? could you be seriesing? could they be seriesing?
Perfect
could I have seriesed? could you have seriesed? could he have seriesed? could we have seriesed? could you have seriesed? could they have seriesed?
V-ing perfect
could I have been seriesing? could you have been seriesing? could he have been seriesing? could we have been seriesing? could you have been seriesing? could they have been seriesing?
Interro-negative form
Simple form
could I not series? could you not series? could he not series? could we not series? could you not series? could they not series?
V-ing form
could I not be seriesing? could you not be seriesing? could he not be seriesing? could we not be seriesing? could you not be seriesing? could they not be seriesing?
Perfect
could I not have seriesed? could you not have seriesed? could he not have seriesed? could we not have seriesed? could you not have seriesed? could they not have seriesed?
V-ing perfect
could I not have been seriesing? could you not have been seriesing? could he not have been seriesing? could we not have been seriesing? could you not have been seriesing? could they not have been seriesing?