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