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 couldn't apologize you couldn't apologize he couldn't apologize we couldn't apologize you couldn't apologize they couldn't apologize
V-ing form
I couldn't be apologizing you couldn't be apologizing he couldn't be apologizing we couldn't be apologizing you couldn't be apologizing they couldn't be apologizing
Perfect
I couldn't have apologized you couldn't have apologized he couldn't have apologized we couldn't have apologized you couldn't have apologized they couldn't have apologized
V-ing perfect
I couldn't have been apologizing you couldn't have been apologizing he couldn't have been apologizing we couldn't have been apologizing you couldn't have been apologizing they couldn't 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
couldn't I apologize? couldn't you apologize? couldn't he apologize? couldn't we apologize? couldn't you apologize? couldn't they apologize?
V-ing form
couldn't I be apologizing? couldn't you be apologizing? couldn't he be apologizing? couldn't we be apologizing? couldn't you be apologizing? couldn't they be apologizing?
Perfect
couldn't I have apologized? couldn't you have apologized? couldn't he have apologized? couldn't we have apologized? couldn't you have apologized? couldn't they have apologized?
V-ing perfect
couldn't I have been apologizing? couldn't you have been apologizing? couldn't he have been apologizing? couldn't we have been apologizing? couldn't you have been apologizing? couldn't they have been apologizing?