English verb conjugation
COULD INTERVENE

Regular verb: intervene - intervened - intervened

Affirmation

Simple form	V-ing form
I could intervene you could intervene he could intervene we could intervene you could intervene they could intervene	I could be intervening you could be intervening he could be intervening we could be intervening you could be intervening they could be intervening
Perfect	V-ing perfect
I could have intervened you could have intervened he could have intervened we could have intervened you could have intervened they could have intervened	I could have been intervening you could have been intervening he could have been intervening we could have been intervening you could have been intervening they could have been intervening

Negation

Simple form	V-ing form
I could not intervene you could not intervene he could not intervene we could not intervene you could not intervene they could not intervene	I could not be intervening you could not be intervening he could not be intervening we could not be intervening you could not be intervening they could not be intervening
Perfect	V-ing perfect
I could not have intervened you could not have intervened he could not have intervened we could not have intervened you could not have intervened they could not have intervened	I could not have been intervening you could not have been intervening he could not have been intervening we could not have been intervening you could not have been intervening they could not have been intervening

Interrogative form

Simple form	V-ing form
could I intervene? could you intervene? could he intervene? could we intervene? could you intervene? could they intervene?	could I be intervening? could you be intervening? could he be intervening? could we be intervening? could you be intervening? could they be intervening?
Perfect	V-ing perfect
could I have intervened? could you have intervened? could he have intervened? could we have intervened? could you have intervened? could they have intervened?	could I have been intervening? could you have been intervening? could he have been intervening? could we have been intervening? could you have been intervening? could they have been intervening?

Interro-negative form

Simple form	V-ing form
could I not intervene? could you not intervene? could he not intervene? could we not intervene? could you not intervene? could they not intervene?	could I not be intervening? could you not be intervening? could he not be intervening? could we not be intervening? could you not be intervening? could they not be intervening?
Perfect	V-ing perfect
could I not have intervened? could you not have intervened? could he not have intervened? could we not have intervened? could you not have intervened? could they not have intervened?	could I not have been intervening? could you not have been intervening? could he not have been intervening? could we not have been intervening? could you not have been intervening? could they not have been intervening?