English verb conjugation
COULD FORM

Regular verb: form - formed - formed

Affirmation

Simple form	V-ing form
I could form you could form she could form we could form you could form they could form	I could be forming you could be forming she could be forming we could be forming you could be forming they could be forming
Perfect	V-ing perfect
I could have formed you could have formed she could have formed we could have formed you could have formed they could have formed	I could have been forming you could have been forming she could have been forming we could have been forming you could have been forming they could have been forming

Negation

Simple form	V-ing form
I could not form you could not form she could not form we could not form you could not form they could not form	I could not be forming you could not be forming she could not be forming we could not be forming you could not be forming they could not be forming
Perfect	V-ing perfect
I could not have formed you could not have formed she could not have formed we could not have formed you could not have formed they could not have formed	I could not have been forming you could not have been forming she could not have been forming we could not have been forming you could not have been forming they could not have been forming

Interrogative form

Simple form	V-ing form
could I form? could you form? could she form? could we form? could you form? could they form?	could I be forming? could you be forming? could she be forming? could we be forming? could you be forming? could they be forming?
Perfect	V-ing perfect
could I have formed? could you have formed? could she have formed? could we have formed? could you have formed? could they have formed?	could I have been forming? could you have been forming? could she have been forming? could we have been forming? could you have been forming? could they have been forming?

Interro-negative form

Simple form	V-ing form
could I not form? could you not form? could she not form? could we not form? could you not form? could they not form?	could I not be forming? could you not be forming? could she not be forming? could we not be forming? could you not be forming? could they not be forming?
Perfect	V-ing perfect
could I not have formed? could you not have formed? could she not have formed? could we not have formed? could you not have formed? could they not have formed?	could I not have been forming? could you not have been forming? could she not have been forming? could we not have been forming? could you not have been forming? could they not have been forming?