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 can't stuff you can't stuff she can't stuff we can't stuff you can't stuff they can't stuff
V-ing form
I can't be stuffing you can't be stuffing she can't be stuffing we can't be stuffing you can't be stuffing they can't be stuffing
Perfect
I can't have stuffed you can't have stuffed she can't have stuffed we can't have stuffed you can't have stuffed they can't have stuffed
V-ing perfect
I can't have been stuffing you can't have been stuffing she can't have been stuffing we can't have been stuffing you can't have been stuffing they can't 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't I stuff? can't you stuff? can't she stuff? can't we stuff? can't you stuff? can't they stuff?
V-ing form
can't I be stuffing? can't you be stuffing? can't she be stuffing? can't we be stuffing? can't you be stuffing? can't they be stuffing?
Perfect
can't I have stuffed? can't you have stuffed? can't she have stuffed? can't we have stuffed? can't you have stuffed? can't they have stuffed?
V-ing perfect
can't I have been stuffing? can't you have been stuffing? can't she have been stuffing? can't we have been stuffing? can't you have been stuffing? can't they have been stuffing?