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