I could touch you could touch he could touch we could touch you could touch they could touch
V-ing form
I could be touching you could be touching he could be touching we could be touching you could be touching they could be touching
Perfect
I could have touched you could have touched he could have touched we could have touched you could have touched they could have touched
V-ing perfect
I could have been touching you could have been touching he could have been touching we could have been touching you could have been touching they could have been touching
Negation
Simple form
I could not touch you could not touch he could not touch we could not touch you could not touch they could not touch
V-ing form
I could not be touching you could not be touching he could not be touching we could not be touching you could not be touching they could not be touching
Perfect
I could not have touched you could not have touched he could not have touched we could not have touched you could not have touched they could not have touched
V-ing perfect
I could not have been touching you could not have been touching he could not have been touching we could not have been touching you could not have been touching they could not have been touching
Interrogative form
Simple form
could I touch? could you touch? could he touch? could we touch? could you touch? could they touch?
V-ing form
could I be touching? could you be touching? could he be touching? could we be touching? could you be touching? could they be touching?
Perfect
could I have touched? could you have touched? could he have touched? could we have touched? could you have touched? could they have touched?
V-ing perfect
could I have been touching? could you have been touching? could he have been touching? could we have been touching? could you have been touching? could they have been touching?
Interro-negative form
Simple form
could I not touch? could you not touch? could he not touch? could we not touch? could you not touch? could they not touch?
V-ing form
could I not be touching? could you not be touching? could he not be touching? could we not be touching? could you not be touching? could they not be touching?
Perfect
could I not have touched? could you not have touched? could he not have touched? could we not have touched? could you not have touched? could they not have touched?
V-ing perfect
could I not have been touching? could you not have been touching? could he not have been touching? could we not have been touching? could you not have been touching? could they not have been touching?