I could seethe you could seethe he could seethe we could seethe you could seethe they could seethe
V-ing form
I could be seething you could be seething he could be seething we could be seething you could be seething they could be seething
Perfect
I could have seethed you could have seethed he could have seethed we could have seethed you could have seethed they could have seethed
V-ing perfect
I could have been seething you could have been seething he could have been seething we could have been seething you could have been seething they could have been seething
Negation
Simple form
I could not seethe you could not seethe he could not seethe we could not seethe you could not seethe they could not seethe
V-ing form
I could not be seething you could not be seething he could not be seething we could not be seething you could not be seething they could not be seething
Perfect
I could not have seethed you could not have seethed he could not have seethed we could not have seethed you could not have seethed they could not have seethed
V-ing perfect
I could not have been seething you could not have been seething he could not have been seething we could not have been seething you could not have been seething they could not have been seething
Interrogative form
Simple form
could I seethe? could you seethe? could he seethe? could we seethe? could you seethe? could they seethe?
V-ing form
could I be seething? could you be seething? could he be seething? could we be seething? could you be seething? could they be seething?
Perfect
could I have seethed? could you have seethed? could he have seethed? could we have seethed? could you have seethed? could they have seethed?
V-ing perfect
could I have been seething? could you have been seething? could he have been seething? could we have been seething? could you have been seething? could they have been seething?
Interro-negative form
Simple form
could I not seethe? could you not seethe? could he not seethe? could we not seethe? could you not seethe? could they not seethe?
V-ing form
could I not be seething? could you not be seething? could he not be seething? could we not be seething? could you not be seething? could they not be seething?
Perfect
could I not have seethed? could you not have seethed? could he not have seethed? could we not have seethed? could you not have seethed? could they not have seethed?
V-ing perfect
could I not have been seething? could you not have been seething? could he not have been seething? could we not have been seething? could you not have been seething? could they not have been seething?