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