I could punch you could punch he could punch we could punch you could punch they could punch
V-ing form
I could be punching you could be punching he could be punching we could be punching you could be punching they could be punching
Perfect
I could have punched you could have punched he could have punched we could have punched you could have punched they could have punched
V-ing perfect
I could have been punching you could have been punching he could have been punching we could have been punching you could have been punching they could have been punching
Negation
Simple form
I could not punch you could not punch he could not punch we could not punch you could not punch they could not punch
V-ing form
I could not be punching you could not be punching he could not be punching we could not be punching you could not be punching they could not be punching
Perfect
I could not have punched you could not have punched he could not have punched we could not have punched you could not have punched they could not have punched
V-ing perfect
I could not have been punching you could not have been punching he could not have been punching we could not have been punching you could not have been punching they could not have been punching
Interrogative form
Simple form
could I punch? could you punch? could he punch? could we punch? could you punch? could they punch?
V-ing form
could I be punching? could you be punching? could he be punching? could we be punching? could you be punching? could they be punching?
Perfect
could I have punched? could you have punched? could he have punched? could we have punched? could you have punched? could they have punched?
V-ing perfect
could I have been punching? could you have been punching? could he have been punching? could we have been punching? could you have been punching? could they have been punching?
Interro-negative form
Simple form
could I not punch? could you not punch? could he not punch? could we not punch? could you not punch? could they not punch?
V-ing form
could I not be punching? could you not be punching? could he not be punching? could we not be punching? could you not be punching? could they not be punching?
Perfect
could I not have punched? could you not have punched? could he not have punched? could we not have punched? could you not have punched? could they not have punched?
V-ing perfect
could I not have been punching? could you not have been punching? could he not have been punching? could we not have been punching? could you not have been punching? could they not have been punching?