I could complement you could complement he could complement we could complement you could complement they could complement
V-ing form
I could be complementing you could be complementing he could be complementing we could be complementing you could be complementing they could be complementing
Perfect
I could have complemented you could have complemented he could have complemented we could have complemented you could have complemented they could have complemented
V-ing perfect
I could have been complementing you could have been complementing he could have been complementing we could have been complementing you could have been complementing they could have been complementing
Negation
Simple form
I could not complement you could not complement he could not complement we could not complement you could not complement they could not complement
V-ing form
I could not be complementing you could not be complementing he could not be complementing we could not be complementing you could not be complementing they could not be complementing
Perfect
I could not have complemented you could not have complemented he could not have complemented we could not have complemented you could not have complemented they could not have complemented
V-ing perfect
I could not have been complementing you could not have been complementing he could not have been complementing we could not have been complementing you could not have been complementing they could not have been complementing
Interrogative form
Simple form
could I complement? could you complement? could he complement? could we complement? could you complement? could they complement?
V-ing form
could I be complementing? could you be complementing? could he be complementing? could we be complementing? could you be complementing? could they be complementing?
Perfect
could I have complemented? could you have complemented? could he have complemented? could we have complemented? could you have complemented? could they have complemented?
V-ing perfect
could I have been complementing? could you have been complementing? could he have been complementing? could we have been complementing? could you have been complementing? could they have been complementing?
Interro-negative form
Simple form
could I not complement? could you not complement? could he not complement? could we not complement? could you not complement? could they not complement?
V-ing form
could I not be complementing? could you not be complementing? could he not be complementing? could we not be complementing? could you not be complementing? could they not be complementing?
Perfect
could I not have complemented? could you not have complemented? could he not have complemented? could we not have complemented? could you not have complemented? could they not have complemented?
V-ing perfect
could I not have been complementing? could you not have been complementing? could he not have been complementing? could we not have been complementing? could you not have been complementing? could they not have been complementing?