I could powder you could powder he could powder we could powder you could powder they could powder
V-ing form
I could be powdering you could be powdering he could be powdering we could be powdering you could be powdering they could be powdering
Perfect
I could have powdered you could have powdered he could have powdered we could have powdered you could have powdered they could have powdered
V-ing perfect
I could have been powdering you could have been powdering he could have been powdering we could have been powdering you could have been powdering they could have been powdering
Negation
Simple form
I could not powder you could not powder he could not powder we could not powder you could not powder they could not powder
V-ing form
I could not be powdering you could not be powdering he could not be powdering we could not be powdering you could not be powdering they could not be powdering
Perfect
I could not have powdered you could not have powdered he could not have powdered we could not have powdered you could not have powdered they could not have powdered
V-ing perfect
I could not have been powdering you could not have been powdering he could not have been powdering we could not have been powdering you could not have been powdering they could not have been powdering
Interrogative form
Simple form
could I powder? could you powder? could he powder? could we powder? could you powder? could they powder?
V-ing form
could I be powdering? could you be powdering? could he be powdering? could we be powdering? could you be powdering? could they be powdering?
Perfect
could I have powdered? could you have powdered? could he have powdered? could we have powdered? could you have powdered? could they have powdered?
V-ing perfect
could I have been powdering? could you have been powdering? could he have been powdering? could we have been powdering? could you have been powdering? could they have been powdering?
Interro-negative form
Simple form
could I not powder? could you not powder? could he not powder? could we not powder? could you not powder? could they not powder?
V-ing form
could I not be powdering? could you not be powdering? could he not be powdering? could we not be powdering? could you not be powdering? could they not be powdering?
Perfect
could I not have powdered? could you not have powdered? could he not have powdered? could we not have powdered? could you not have powdered? could they not have powdered?
V-ing perfect
could I not have been powdering? could you not have been powdering? could he not have been powdering? could we not have been powdering? could you not have been powdering? could they not have been powdering?