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