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