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