I could perish you could perish she could perish we could perish you could perish they could perish
V-ing form
I could be perishing you could be perishing she could be perishing we could be perishing you could be perishing they could be perishing
Perfect
I could have perished you could have perished she could have perished we could have perished you could have perished they could have perished
V-ing perfect
I could have been perishing you could have been perishing she could have been perishing we could have been perishing you could have been perishing they could have been perishing
Negation
Simple form
I could not perish you could not perish she could not perish we could not perish you could not perish they could not perish
V-ing form
I could not be perishing you could not be perishing she could not be perishing we could not be perishing you could not be perishing they could not be perishing
Perfect
I could not have perished you could not have perished she could not have perished we could not have perished you could not have perished they could not have perished
V-ing perfect
I could not have been perishing you could not have been perishing she could not have been perishing we could not have been perishing you could not have been perishing they could not have been perishing
Interrogative form
Simple form
could I perish? could you perish? could she perish? could we perish? could you perish? could they perish?
V-ing form
could I be perishing? could you be perishing? could she be perishing? could we be perishing? could you be perishing? could they be perishing?
Perfect
could I have perished? could you have perished? could she have perished? could we have perished? could you have perished? could they have perished?
V-ing perfect
could I have been perishing? could you have been perishing? could she have been perishing? could we have been perishing? could you have been perishing? could they have been perishing?
Interro-negative form
Simple form
could I not perish? could you not perish? could she not perish? could we not perish? could you not perish? could they not perish?
V-ing form
could I not be perishing? could you not be perishing? could she not be perishing? could we not be perishing? could you not be perishing? could they not be perishing?
Perfect
could I not have perished? could you not have perished? could she not have perished? could we not have perished? could you not have perished? could they not have perished?
V-ing perfect
could I not have been perishing? could you not have been perishing? could she not have been perishing? could we not have been perishing? could you not have been perishing? could they not have been perishing?