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