I could watch you could watch he could watch we could watch you could watch they could watch
V-ing form
I could be watching you could be watching he could be watching we could be watching you could be watching they could be watching
Perfect
I could have watched you could have watched he could have watched we could have watched you could have watched they could have watched
V-ing perfect
I could have been watching you could have been watching he could have been watching we could have been watching you could have been watching they could have been watching
Negation
Simple form
I could not watch you could not watch he could not watch we could not watch you could not watch they could not watch
V-ing form
I could not be watching you could not be watching he could not be watching we could not be watching you could not be watching they could not be watching
Perfect
I could not have watched you could not have watched he could not have watched we could not have watched you could not have watched they could not have watched
V-ing perfect
I could not have been watching you could not have been watching he could not have been watching we could not have been watching you could not have been watching they could not have been watching
Interrogative form
Simple form
could I watch? could you watch? could he watch? could we watch? could you watch? could they watch?
V-ing form
could I be watching? could you be watching? could he be watching? could we be watching? could you be watching? could they be watching?
Perfect
could I have watched? could you have watched? could he have watched? could we have watched? could you have watched? could they have watched?
V-ing perfect
could I have been watching? could you have been watching? could he have been watching? could we have been watching? could you have been watching? could they have been watching?
Interro-negative form
Simple form
could I not watch? could you not watch? could he not watch? could we not watch? could you not watch? could they not watch?
V-ing form
could I not be watching? could you not be watching? could he not be watching? could we not be watching? could you not be watching? could they not be watching?
Perfect
could I not have watched? could you not have watched? could he not have watched? could we not have watched? could you not have watched? could they not have watched?
V-ing perfect
could I not have been watching? could you not have been watching? could he not have been watching? could we not have been watching? could you not have been watching? could they not have been watching?