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