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