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