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