I could concede you could concede he could concede we could concede you could concede they could concede
V-ing form
I could be conceding you could be conceding he could be conceding we could be conceding you could be conceding they could be conceding
Perfect
I could have conceded you could have conceded he could have conceded we could have conceded you could have conceded they could have conceded
V-ing perfect
I could have been conceding you could have been conceding he could have been conceding we could have been conceding you could have been conceding they could have been conceding
Negation
Simple form
I couldn't concede you couldn't concede he couldn't concede we couldn't concede you couldn't concede they couldn't concede
V-ing form
I couldn't be conceding you couldn't be conceding he couldn't be conceding we couldn't be conceding you couldn't be conceding they couldn't be conceding
Perfect
I couldn't have conceded you couldn't have conceded he couldn't have conceded we couldn't have conceded you couldn't have conceded they couldn't have conceded
V-ing perfect
I couldn't have been conceding you couldn't have been conceding he couldn't have been conceding we couldn't have been conceding you couldn't have been conceding they couldn't have been conceding
Interrogative form
Simple form
could I concede? could you concede? could he concede? could we concede? could you concede? could they concede?
V-ing form
could I be conceding? could you be conceding? could he be conceding? could we be conceding? could you be conceding? could they be conceding?
Perfect
could I have conceded? could you have conceded? could he have conceded? could we have conceded? could you have conceded? could they have conceded?
V-ing perfect
could I have been conceding? could you have been conceding? could he have been conceding? could we have been conceding? could you have been conceding? could they have been conceding?
Interro-negative form
Simple form
couldn't I concede? couldn't you concede? couldn't he concede? couldn't we concede? couldn't you concede? couldn't they concede?
V-ing form
couldn't I be conceding? couldn't you be conceding? couldn't he be conceding? couldn't we be conceding? couldn't you be conceding? couldn't they be conceding?
Perfect
couldn't I have conceded? couldn't you have conceded? couldn't he have conceded? couldn't we have conceded? couldn't you have conceded? couldn't they have conceded?
V-ing perfect
couldn't I have been conceding? couldn't you have been conceding? couldn't he have been conceding? couldn't we have been conceding? couldn't you have been conceding? couldn't they have been conceding?