I could apologize you could apologize he could apologize we could apologize you could apologize they could apologize
V-ing form
I could be apologizing you could be apologizing he could be apologizing we could be apologizing you could be apologizing they could be apologizing
Perfect
I could have apologized you could have apologized he could have apologized we could have apologized you could have apologized they could have apologized
V-ing perfect
I could have been apologizing you could have been apologizing he could have been apologizing we could have been apologizing you could have been apologizing they could have been apologizing
Negation
Simple form
I could not apologize you could not apologize he could not apologize we could not apologize you could not apologize they could not apologize
V-ing form
I could not be apologizing you could not be apologizing he could not be apologizing we could not be apologizing you could not be apologizing they could not be apologizing
Perfect
I could not have apologized you could not have apologized he could not have apologized we could not have apologized you could not have apologized they could not have apologized
V-ing perfect
I could not have been apologizing you could not have been apologizing he could not have been apologizing we could not have been apologizing you could not have been apologizing they could not have been apologizing
Interrogative form
Simple form
could I apologize? could you apologize? could he apologize? could we apologize? could you apologize? could they apologize?
V-ing form
could I be apologizing? could you be apologizing? could he be apologizing? could we be apologizing? could you be apologizing? could they be apologizing?
Perfect
could I have apologized? could you have apologized? could he have apologized? could we have apologized? could you have apologized? could they have apologized?
V-ing perfect
could I have been apologizing? could you have been apologizing? could he have been apologizing? could we have been apologizing? could you have been apologizing? could they have been apologizing?
Interro-negative form
Simple form
could I not apologize? could you not apologize? could he not apologize? could we not apologize? could you not apologize? could they not apologize?
V-ing form
could I not be apologizing? could you not be apologizing? could he not be apologizing? could we not be apologizing? could you not be apologizing? could they not be apologizing?
Perfect
could I not have apologized? could you not have apologized? could he not have apologized? could we not have apologized? could you not have apologized? could they not have apologized?
V-ing perfect
could I not have been apologizing? could you not have been apologizing? could he not have been apologizing? could we not have been apologizing? could you not have been apologizing? could they not have been apologizing?