English verb conjugation
COULD INVENT

Regular verb: invent - invented - invented

Affirmation

Simple form	V-ing form
I could invent you could invent he could invent we could invent you could invent they could invent	I could be inventing you could be inventing he could be inventing we could be inventing you could be inventing they could be inventing
Perfect	V-ing perfect
I could have invented you could have invented he could have invented we could have invented you could have invented they could have invented	I could have been inventing you could have been inventing he could have been inventing we could have been inventing you could have been inventing they could have been inventing

Negation

Simple form	V-ing form
I could not invent you could not invent he could not invent we could not invent you could not invent they could not invent	I could not be inventing you could not be inventing he could not be inventing we could not be inventing you could not be inventing they could not be inventing
Perfect	V-ing perfect
I could not have invented you could not have invented he could not have invented we could not have invented you could not have invented they could not have invented	I could not have been inventing you could not have been inventing he could not have been inventing we could not have been inventing you could not have been inventing they could not have been inventing

Interrogative form

Simple form	V-ing form
could I invent? could you invent? could he invent? could we invent? could you invent? could they invent?	could I be inventing? could you be inventing? could he be inventing? could we be inventing? could you be inventing? could they be inventing?
Perfect	V-ing perfect
could I have invented? could you have invented? could he have invented? could we have invented? could you have invented? could they have invented?	could I have been inventing? could you have been inventing? could he have been inventing? could we have been inventing? could you have been inventing? could they have been inventing?

Interro-negative form

Simple form	V-ing form
could I not invent? could you not invent? could he not invent? could we not invent? could you not invent? could they not invent?	could I not be inventing? could you not be inventing? could he not be inventing? could we not be inventing? could you not be inventing? could they not be inventing?
Perfect	V-ing perfect
could I not have invented? could you not have invented? could he not have invented? could we not have invented? could you not have invented? could they not have invented?	could I not have been inventing? could you not have been inventing? could he not have been inventing? could we not have been inventing? could you not have been inventing? could they not have been inventing?