I could trot you could trot she could trot we could trot you could trot they could trot
V-ing form
I could be trotting you could be trotting she could be trotting we could be trotting you could be trotting they could be trotting
Perfect
I could have trotted you could have trotted she could have trotted we could have trotted you could have trotted they could have trotted
V-ing perfect
I could have been trotting you could have been trotting she could have been trotting we could have been trotting you could have been trotting they could have been trotting
Negation
Simple form
I could not trot you could not trot she could not trot we could not trot you could not trot they could not trot
V-ing form
I could not be trotting you could not be trotting she could not be trotting we could not be trotting you could not be trotting they could not be trotting
Perfect
I could not have trotted you could not have trotted she could not have trotted we could not have trotted you could not have trotted they could not have trotted
V-ing perfect
I could not have been trotting you could not have been trotting she could not have been trotting we could not have been trotting you could not have been trotting they could not have been trotting
Interrogative form
Simple form
could I trot? could you trot? could she trot? could we trot? could you trot? could they trot?
V-ing form
could I be trotting? could you be trotting? could she be trotting? could we be trotting? could you be trotting? could they be trotting?
Perfect
could I have trotted? could you have trotted? could she have trotted? could we have trotted? could you have trotted? could they have trotted?
V-ing perfect
could I have been trotting? could you have been trotting? could she have been trotting? could we have been trotting? could you have been trotting? could they have been trotting?
Interro-negative form
Simple form
could I not trot? could you not trot? could she not trot? could we not trot? could you not trot? could they not trot?
V-ing form
could I not be trotting? could you not be trotting? could she not be trotting? could we not be trotting? could you not be trotting? could they not be trotting?
Perfect
could I not have trotted? could you not have trotted? could she not have trotted? could we not have trotted? could you not have trotted? could they not have trotted?
V-ing perfect
could I not have been trotting? could you not have been trotting? could she not have been trotting? could we not have been trotting? could you not have been trotting? could they not have been trotting?