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