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 couldn't perish you couldn't perish she couldn't perish we couldn't perish you couldn't perish they couldn't perish
V-ing form
I couldn't be perishing you couldn't be perishing she couldn't be perishing we couldn't be perishing you couldn't be perishing they couldn't be perishing
Perfect
I couldn't have perished you couldn't have perished she couldn't have perished we couldn't have perished you couldn't have perished they couldn't have perished
V-ing perfect
I couldn't have been perishing you couldn't have been perishing she couldn't have been perishing we couldn't have been perishing you couldn't have been perishing they couldn't 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
couldn't I perish? couldn't you perish? couldn't she perish? couldn't we perish? couldn't you perish? couldn't they perish?
V-ing form
couldn't I be perishing? couldn't you be perishing? couldn't she be perishing? couldn't we be perishing? couldn't you be perishing? couldn't they be perishing?
Perfect
couldn't I have perished? couldn't you have perished? couldn't she have perished? couldn't we have perished? couldn't you have perished? couldn't they have perished?
V-ing perfect
couldn't I have been perishing? couldn't you have been perishing? couldn't she have been perishing? couldn't we have been perishing? couldn't you have been perishing? couldn't they have been perishing?