I could adopt you could adopt he could adopt we could adopt you could adopt they could adopt
V-ing form
I could be adopting you could be adopting he could be adopting we could be adopting you could be adopting they could be adopting
Perfect
I could have adopted you could have adopted he could have adopted we could have adopted you could have adopted they could have adopted
V-ing perfect
I could have been adopting you could have been adopting he could have been adopting we could have been adopting you could have been adopting they could have been adopting
Negation
Simple form
I could not adopt you could not adopt he could not adopt we could not adopt you could not adopt they could not adopt
V-ing form
I could not be adopting you could not be adopting he could not be adopting we could not be adopting you could not be adopting they could not be adopting
Perfect
I could not have adopted you could not have adopted he could not have adopted we could not have adopted you could not have adopted they could not have adopted
V-ing perfect
I could not have been adopting you could not have been adopting he could not have been adopting we could not have been adopting you could not have been adopting they could not have been adopting
Interrogative form
Simple form
could I adopt? could you adopt? could he adopt? could we adopt? could you adopt? could they adopt?
V-ing form
could I be adopting? could you be adopting? could he be adopting? could we be adopting? could you be adopting? could they be adopting?
Perfect
could I have adopted? could you have adopted? could he have adopted? could we have adopted? could you have adopted? could they have adopted?
V-ing perfect
could I have been adopting? could you have been adopting? could he have been adopting? could we have been adopting? could you have been adopting? could they have been adopting?
Interro-negative form
Simple form
could I not adopt? could you not adopt? could he not adopt? could we not adopt? could you not adopt? could they not adopt?
V-ing form
could I not be adopting? could you not be adopting? could he not be adopting? could we not be adopting? could you not be adopting? could they not be adopting?
Perfect
could I not have adopted? could you not have adopted? could he not have adopted? could we not have adopted? could you not have adopted? could they not have adopted?
V-ing perfect
could I not have been adopting? could you not have been adopting? could he not have been adopting? could we not have been adopting? could you not have been adopting? could they not have been adopting?