I could tow you could tow he could tow we could tow you could tow they could tow
V-ing form
I could be towing you could be towing he could be towing we could be towing you could be towing they could be towing
Perfect
I could have towed you could have towed he could have towed we could have towed you could have towed they could have towed
V-ing perfect
I could have been towing you could have been towing he could have been towing we could have been towing you could have been towing they could have been towing
Negation
Simple form
I couldn't tow you couldn't tow he couldn't tow we couldn't tow you couldn't tow they couldn't tow
V-ing form
I couldn't be towing you couldn't be towing he couldn't be towing we couldn't be towing you couldn't be towing they couldn't be towing
Perfect
I couldn't have towed you couldn't have towed he couldn't have towed we couldn't have towed you couldn't have towed they couldn't have towed
V-ing perfect
I couldn't have been towing you couldn't have been towing he couldn't have been towing we couldn't have been towing you couldn't have been towing they couldn't have been towing
Interrogative form
Simple form
could I tow? could you tow? could he tow? could we tow? could you tow? could they tow?
V-ing form
could I be towing? could you be towing? could he be towing? could we be towing? could you be towing? could they be towing?
Perfect
could I have towed? could you have towed? could he have towed? could we have towed? could you have towed? could they have towed?
V-ing perfect
could I have been towing? could you have been towing? could he have been towing? could we have been towing? could you have been towing? could they have been towing?
Interro-negative form
Simple form
couldn't I tow? couldn't you tow? couldn't he tow? couldn't we tow? couldn't you tow? couldn't they tow?
V-ing form
couldn't I be towing? couldn't you be towing? couldn't he be towing? couldn't we be towing? couldn't you be towing? couldn't they be towing?
Perfect
couldn't I have towed? couldn't you have towed? couldn't he have towed? couldn't we have towed? couldn't you have towed? couldn't they have towed?
V-ing perfect
couldn't I have been towing? couldn't you have been towing? couldn't he have been towing? couldn't we have been towing? couldn't you have been towing? couldn't they have been towing?