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