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