English verb conjugation
COULD CHANGE

Regular verb: change - changed - changed

Affirmation

Simple form	V-ing form
I could change you could change he could change we could change you could change they could change	I could be changing you could be changing he could be changing we could be changing you could be changing they could be changing
Perfect	V-ing perfect
I could have changed you could have changed he could have changed we could have changed you could have changed they could have changed	I could have been changing you could have been changing he could have been changing we could have been changing you could have been changing they could have been changing

Negation

Simple form	V-ing form
I could not change you could not change he could not change we could not change you could not change they could not change	I could not be changing you could not be changing he could not be changing we could not be changing you could not be changing they could not be changing
Perfect	V-ing perfect
I could not have changed you could not have changed he could not have changed we could not have changed you could not have changed they could not have changed	I could not have been changing you could not have been changing he could not have been changing we could not have been changing you could not have been changing they could not have been changing

Interrogative form

Simple form	V-ing form
could I change? could you change? could he change? could we change? could you change? could they change?	could I be changing? could you be changing? could he be changing? could we be changing? could you be changing? could they be changing?
Perfect	V-ing perfect
could I have changed? could you have changed? could he have changed? could we have changed? could you have changed? could they have changed?	could I have been changing? could you have been changing? could he have been changing? could we have been changing? could you have been changing? could they have been changing?

Interro-negative form

Simple form	V-ing form
could I not change? could you not change? could he not change? could we not change? could you not change? could they not change?	could I not be changing? could you not be changing? could he not be changing? could we not be changing? could you not be changing? could they not be changing?
Perfect	V-ing perfect
could I not have changed? could you not have changed? could he not have changed? could we not have changed? could you not have changed? could they not have changed?	could I not have been changing? could you not have been changing? could he not have been changing? could we not have been changing? could you not have been changing? could they not have been changing?