English verb conjugation
COULD FLATTEN

Regular verb: flatten - flattened - flattened

Affirmation

Simple form	V-ing form
I could flatten you could flatten he could flatten we could flatten you could flatten they could flatten	I could be flattening you could be flattening he could be flattening we could be flattening you could be flattening they could be flattening
Perfect	V-ing perfect
I could have flattened you could have flattened he could have flattened we could have flattened you could have flattened they could have flattened	I could have been flattening you could have been flattening he could have been flattening we could have been flattening you could have been flattening they could have been flattening

Negation

Simple form	V-ing form
I could not flatten you could not flatten he could not flatten we could not flatten you could not flatten they could not flatten	I could not be flattening you could not be flattening he could not be flattening we could not be flattening you could not be flattening they could not be flattening
Perfect	V-ing perfect
I could not have flattened you could not have flattened he could not have flattened we could not have flattened you could not have flattened they could not have flattened	I could not have been flattening you could not have been flattening he could not have been flattening we could not have been flattening you could not have been flattening they could not have been flattening

Interrogative form

Simple form	V-ing form
could I flatten? could you flatten? could he flatten? could we flatten? could you flatten? could they flatten?	could I be flattening? could you be flattening? could he be flattening? could we be flattening? could you be flattening? could they be flattening?
Perfect	V-ing perfect
could I have flattened? could you have flattened? could he have flattened? could we have flattened? could you have flattened? could they have flattened?	could I have been flattening? could you have been flattening? could he have been flattening? could we have been flattening? could you have been flattening? could they have been flattening?

Interro-negative form

Simple form	V-ing form
could I not flatten? could you not flatten? could he not flatten? could we not flatten? could you not flatten? could they not flatten?	could I not be flattening? could you not be flattening? could he not be flattening? could we not be flattening? could you not be flattening? could they not be flattening?
Perfect	V-ing perfect
could I not have flattened? could you not have flattened? could he not have flattened? could we not have flattened? could you not have flattened? could they not have flattened?	could I not have been flattening? could you not have been flattening? could he not have been flattening? could we not have been flattening? could you not have been flattening? could they not have been flattening?