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 couldn't seethe you couldn't seethe he couldn't seethe we couldn't seethe you couldn't seethe they couldn't seethe
V-ing form
I couldn't be seething you couldn't be seething he couldn't be seething we couldn't be seething you couldn't be seething they couldn't be seething
Perfect
I couldn't have seethed you couldn't have seethed he couldn't have seethed we couldn't have seethed you couldn't have seethed they couldn't have seethed
V-ing perfect
I couldn't have been seething you couldn't have been seething he couldn't have been seething we couldn't have been seething you couldn't have been seething they couldn't 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
couldn't I seethe? couldn't you seethe? couldn't he seethe? couldn't we seethe? couldn't you seethe? couldn't they seethe?
V-ing form
couldn't I be seething? couldn't you be seething? couldn't he be seething? couldn't we be seething? couldn't you be seething? couldn't they be seething?
Perfect
couldn't I have seethed? couldn't you have seethed? couldn't he have seethed? couldn't we have seethed? couldn't you have seethed? couldn't they have seethed?
V-ing perfect
couldn't I have been seething? couldn't you have been seething? couldn't he have been seething? couldn't we have been seething? couldn't you have been seething? couldn't they have been seething?