I could tether you could tether he could tether we could tether you could tether they could tether
V-ing form
I could be tethering you could be tethering he could be tethering we could be tethering you could be tethering they could be tethering
Perfect
I could have tethered you could have tethered he could have tethered we could have tethered you could have tethered they could have tethered
V-ing perfect
I could have been tethering you could have been tethering he could have been tethering we could have been tethering you could have been tethering they could have been tethering
Negation
Simple form
I could not tether you could not tether he could not tether we could not tether you could not tether they could not tether
V-ing form
I could not be tethering you could not be tethering he could not be tethering we could not be tethering you could not be tethering they could not be tethering
Perfect
I could not have tethered you could not have tethered he could not have tethered we could not have tethered you could not have tethered they could not have tethered
V-ing perfect
I could not have been tethering you could not have been tethering he could not have been tethering we could not have been tethering you could not have been tethering they could not have been tethering
Interrogative form
Simple form
could I tether? could you tether? could he tether? could we tether? could you tether? could they tether?
V-ing form
could I be tethering? could you be tethering? could he be tethering? could we be tethering? could you be tethering? could they be tethering?
Perfect
could I have tethered? could you have tethered? could he have tethered? could we have tethered? could you have tethered? could they have tethered?
V-ing perfect
could I have been tethering? could you have been tethering? could he have been tethering? could we have been tethering? could you have been tethering? could they have been tethering?
Interro-negative form
Simple form
could I not tether? could you not tether? could he not tether? could we not tether? could you not tether? could they not tether?
V-ing form
could I not be tethering? could you not be tethering? could he not be tethering? could we not be tethering? could you not be tethering? could they not be tethering?
Perfect
could I not have tethered? could you not have tethered? could he not have tethered? could we not have tethered? could you not have tethered? could they not have tethered?
V-ing perfect
could I not have been tethering? could you not have been tethering? could he not have been tethering? could we not have been tethering? could you not have been tethering? could they not have been tethering?