I could perfect you could perfect she could perfect we could perfect you could perfect they could perfect
V-ing form
I could be perfecting you could be perfecting she could be perfecting we could be perfecting you could be perfecting they could be perfecting
Perfect
I could have perfected you could have perfected she could have perfected we could have perfected you could have perfected they could have perfected
V-ing perfect
I could have been perfecting you could have been perfecting she could have been perfecting we could have been perfecting you could have been perfecting they could have been perfecting
Negation
Simple form
I could not perfect you could not perfect she could not perfect we could not perfect you could not perfect they could not perfect
V-ing form
I could not be perfecting you could not be perfecting she could not be perfecting we could not be perfecting you could not be perfecting they could not be perfecting
Perfect
I could not have perfected you could not have perfected she could not have perfected we could not have perfected you could not have perfected they could not have perfected
V-ing perfect
I could not have been perfecting you could not have been perfecting she could not have been perfecting we could not have been perfecting you could not have been perfecting they could not have been perfecting
Interrogative form
Simple form
could I perfect? could you perfect? could she perfect? could we perfect? could you perfect? could they perfect?
V-ing form
could I be perfecting? could you be perfecting? could she be perfecting? could we be perfecting? could you be perfecting? could they be perfecting?
Perfect
could I have perfected? could you have perfected? could she have perfected? could we have perfected? could you have perfected? could they have perfected?
V-ing perfect
could I have been perfecting? could you have been perfecting? could she have been perfecting? could we have been perfecting? could you have been perfecting? could they have been perfecting?
Interro-negative form
Simple form
could I not perfect? could you not perfect? could she not perfect? could we not perfect? could you not perfect? could they not perfect?
V-ing form
could I not be perfecting? could you not be perfecting? could she not be perfecting? could we not be perfecting? could you not be perfecting? could they not be perfecting?
Perfect
could I not have perfected? could you not have perfected? could she not have perfected? could we not have perfected? could you not have perfected? could they not have perfected?
V-ing perfect
could I not have been perfecting? could you not have been perfecting? could she not have been perfecting? could we not have been perfecting? could you not have been perfecting? could they not have been perfecting?