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 couldn't tether you couldn't tether he couldn't tether we couldn't tether you couldn't tether they couldn't tether
V-ing form
I couldn't be tethering you couldn't be tethering he couldn't be tethering we couldn't be tethering you couldn't be tethering they couldn't be tethering
Perfect
I couldn't have tethered you couldn't have tethered he couldn't have tethered we couldn't have tethered you couldn't have tethered they couldn't have tethered
V-ing perfect
I couldn't have been tethering you couldn't have been tethering he couldn't have been tethering we couldn't have been tethering you couldn't have been tethering they couldn't 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
couldn't I tether? couldn't you tether? couldn't he tether? couldn't we tether? couldn't you tether? couldn't they tether?
V-ing form
couldn't I be tethering? couldn't you be tethering? couldn't he be tethering? couldn't we be tethering? couldn't you be tethering? couldn't they be tethering?
Perfect
couldn't I have tethered? couldn't you have tethered? couldn't he have tethered? couldn't we have tethered? couldn't you have tethered? couldn't they have tethered?
V-ing perfect
couldn't I have been tethering? couldn't you have been tethering? couldn't he have been tethering? couldn't we have been tethering? couldn't you have been tethering? couldn't they have been tethering?