English verb conjugation
COULD STOP

Regular verb: stop - stopped - stopped

Affirmation

Simple form	V-ing form
I could stop you could stop he could stop we could stop you could stop they could stop	I could be stopping you could be stopping he could be stopping we could be stopping you could be stopping they could be stopping
Perfect	V-ing perfect
I could have stopped you could have stopped he could have stopped we could have stopped you could have stopped they could have stopped	I could have been stopping you could have been stopping he could have been stopping we could have been stopping you could have been stopping they could have been stopping

Negation

Simple form	V-ing form
I could not stop you could not stop he could not stop we could not stop you could not stop they could not stop	I could not be stopping you could not be stopping he could not be stopping we could not be stopping you could not be stopping they could not be stopping
Perfect	V-ing perfect
I could not have stopped you could not have stopped he could not have stopped we could not have stopped you could not have stopped they could not have stopped	I could not have been stopping you could not have been stopping he could not have been stopping we could not have been stopping you could not have been stopping they could not have been stopping

Interrogative form

Simple form	V-ing form
could I stop? could you stop? could he stop? could we stop? could you stop? could they stop?	could I be stopping? could you be stopping? could he be stopping? could we be stopping? could you be stopping? could they be stopping?
Perfect	V-ing perfect
could I have stopped? could you have stopped? could he have stopped? could we have stopped? could you have stopped? could they have stopped?	could I have been stopping? could you have been stopping? could he have been stopping? could we have been stopping? could you have been stopping? could they have been stopping?

Interro-negative form

Simple form	V-ing form
could I not stop? could you not stop? could he not stop? could we not stop? could you not stop? could they not stop?	could I not be stopping? could you not be stopping? could he not be stopping? could we not be stopping? could you not be stopping? could they not be stopping?
Perfect	V-ing perfect
could I not have stopped? could you not have stopped? could he not have stopped? could we not have stopped? could you not have stopped? could they not have stopped?	could I not have been stopping? could you not have been stopping? could he not have been stopping? could we not have been stopping? could you not have been stopping? could they not have been stopping?