English verb conjugation
COULD BUTTRESS

Regular verb: buttress - buttressed - buttressed

Affirmation

Simple form	V-ing form
I could buttress you could buttress he could buttress we could buttress you could buttress they could buttress	I could be buttressing you could be buttressing he could be buttressing we could be buttressing you could be buttressing they could be buttressing
Perfect	V-ing perfect
I could have buttressed you could have buttressed he could have buttressed we could have buttressed you could have buttressed they could have buttressed	I could have been buttressing you could have been buttressing he could have been buttressing we could have been buttressing you could have been buttressing they could have been buttressing

Negation

Simple form	V-ing form
I couldn't buttress you couldn't buttress he couldn't buttress we couldn't buttress you couldn't buttress they couldn't buttress	I couldn't be buttressing you couldn't be buttressing he couldn't be buttressing we couldn't be buttressing you couldn't be buttressing they couldn't be buttressing
Perfect	V-ing perfect
I couldn't have buttressed you couldn't have buttressed he couldn't have buttressed we couldn't have buttressed you couldn't have buttressed they couldn't have buttressed	I couldn't have been buttressing you couldn't have been buttressing he couldn't have been buttressing we couldn't have been buttressing you couldn't have been buttressing they couldn't have been buttressing

Interrogative form

Simple form	V-ing form
could I buttress? could you buttress? could he buttress? could we buttress? could you buttress? could they buttress?	could I be buttressing? could you be buttressing? could he be buttressing? could we be buttressing? could you be buttressing? could they be buttressing?
Perfect	V-ing perfect
could I have buttressed? could you have buttressed? could he have buttressed? could we have buttressed? could you have buttressed? could they have buttressed?	could I have been buttressing? could you have been buttressing? could he have been buttressing? could we have been buttressing? could you have been buttressing? could they have been buttressing?

Interro-negative form

Simple form	V-ing form
couldn't I buttress? couldn't you buttress? couldn't he buttress? couldn't we buttress? couldn't you buttress? couldn't they buttress?	couldn't I be buttressing? couldn't you be buttressing? couldn't he be buttressing? couldn't we be buttressing? couldn't you be buttressing? couldn't they be buttressing?
Perfect	V-ing perfect
couldn't I have buttressed? couldn't you have buttressed? couldn't he have buttressed? couldn't we have buttressed? couldn't you have buttressed? couldn't they have buttressed?	couldn't I have been buttressing? couldn't you have been buttressing? couldn't he have been buttressing? couldn't we have been buttressing? couldn't you have been buttressing? couldn't they have been buttressing?