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