I could depart you could depart he could depart we could depart you could depart they could depart
V-ing form
I could be departing you could be departing he could be departing we could be departing you could be departing they could be departing
Perfect
I could have departed you could have departed he could have departed we could have departed you could have departed they could have departed
V-ing perfect
I could have been departing you could have been departing he could have been departing we could have been departing you could have been departing they could have been departing
Negation
Simple form
I could not depart you could not depart he could not depart we could not depart you could not depart they could not depart
V-ing form
I could not be departing you could not be departing he could not be departing we could not be departing you could not be departing they could not be departing
Perfect
I could not have departed you could not have departed he could not have departed we could not have departed you could not have departed they could not have departed
V-ing perfect
I could not have been departing you could not have been departing he could not have been departing we could not have been departing you could not have been departing they could not have been departing
Interrogative form
Simple form
could I depart? could you depart? could he depart? could we depart? could you depart? could they depart?
V-ing form
could I be departing? could you be departing? could he be departing? could we be departing? could you be departing? could they be departing?
Perfect
could I have departed? could you have departed? could he have departed? could we have departed? could you have departed? could they have departed?
V-ing perfect
could I have been departing? could you have been departing? could he have been departing? could we have been departing? could you have been departing? could they have been departing?
Interro-negative form
Simple form
could I not depart? could you not depart? could he not depart? could we not depart? could you not depart? could they not depart?
V-ing form
could I not be departing? could you not be departing? could he not be departing? could we not be departing? could you not be departing? could they not be departing?
Perfect
could I not have departed? could you not have departed? could he not have departed? could we not have departed? could you not have departed? could they not have departed?
V-ing perfect
could I not have been departing? could you not have been departing? could he not have been departing? could we not have been departing? could you not have been departing? could they not have been departing?