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