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