I can butt you can butt he can butt we can butt you can butt they can butt
V-ing form
I can be butting you can be butting he can be butting we can be butting you can be butting they can be butting
Perfect
I can have butted you can have butted he can have butted we can have butted you can have butted they can have butted
V-ing perfect
I can have been butting you can have been butting he can have been butting we can have been butting you can have been butting they can have been butting
Negation
Simple form
I can't butt you can't butt he can't butt we can't butt you can't butt they can't butt
V-ing form
I can't be butting you can't be butting he can't be butting we can't be butting you can't be butting they can't be butting
Perfect
I can't have butted you can't have butted he can't have butted we can't have butted you can't have butted they can't have butted
V-ing perfect
I can't have been butting you can't have been butting he can't have been butting we can't have been butting you can't have been butting they can't have been butting
Interrogative form
Simple form
can I butt? can you butt? can he butt? can we butt? can you butt? can they butt?
V-ing form
can I be butting? can you be butting? can he be butting? can we be butting? can you be butting? can they be butting?
Perfect
can I have butted? can you have butted? can he have butted? can we have butted? can you have butted? can they have butted?
V-ing perfect
can I have been butting? can you have been butting? can he have been butting? can we have been butting? can you have been butting? can they have been butting?
Interro-negative form
Simple form
can't I butt? can't you butt? can't he butt? can't we butt? can't you butt? can't they butt?
V-ing form
can't I be butting? can't you be butting? can't he be butting? can't we be butting? can't you be butting? can't they be butting?
Perfect
can't I have butted? can't you have butted? can't he have butted? can't we have butted? can't you have butted? can't they have butted?
V-ing perfect
can't I have been butting? can't you have been butting? can't he have been butting? can't we have been butting? can't you have been butting? can't they have been butting?