English verb conjugation
COULD FIRM

Regular verb: firm - firmed - firmed

Affirmation

Simple form	V-ing form
I could firm you could firm she could firm we could firm you could firm they could firm	I could be firming you could be firming she could be firming we could be firming you could be firming they could be firming
Perfect	V-ing perfect
I could have firmed you could have firmed she could have firmed we could have firmed you could have firmed they could have firmed	I could have been firming you could have been firming she could have been firming we could have been firming you could have been firming they could have been firming

Negation

Simple form	V-ing form
I couldn't firm you couldn't firm she couldn't firm we couldn't firm you couldn't firm they couldn't firm	I couldn't be firming you couldn't be firming she couldn't be firming we couldn't be firming you couldn't be firming they couldn't be firming
Perfect	V-ing perfect
I couldn't have firmed you couldn't have firmed she couldn't have firmed we couldn't have firmed you couldn't have firmed they couldn't have firmed	I couldn't have been firming you couldn't have been firming she couldn't have been firming we couldn't have been firming you couldn't have been firming they couldn't have been firming

Interrogative form

Simple form	V-ing form
could I firm? could you firm? could she firm? could we firm? could you firm? could they firm?	could I be firming? could you be firming? could she be firming? could we be firming? could you be firming? could they be firming?
Perfect	V-ing perfect
could I have firmed? could you have firmed? could she have firmed? could we have firmed? could you have firmed? could they have firmed?	could I have been firming? could you have been firming? could she have been firming? could we have been firming? could you have been firming? could they have been firming?

Interro-negative form

Simple form	V-ing form
couldn't I firm? couldn't you firm? couldn't she firm? couldn't we firm? couldn't you firm? couldn't they firm?	couldn't I be firming? couldn't you be firming? couldn't she be firming? couldn't we be firming? couldn't you be firming? couldn't they be firming?
Perfect	V-ing perfect
couldn't I have firmed? couldn't you have firmed? couldn't she have firmed? couldn't we have firmed? couldn't you have firmed? couldn't they have firmed?	couldn't I have been firming? couldn't you have been firming? couldn't she have been firming? couldn't we have been firming? couldn't you have been firming? couldn't they have been firming?