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