I could nab you could nab he could nab we could nab you could nab they could nab
V-ing form
I could be nabbing you could be nabbing he could be nabbing we could be nabbing you could be nabbing they could be nabbing
Perfect
I could have nabbed you could have nabbed he could have nabbed we could have nabbed you could have nabbed they could have nabbed
V-ing perfect
I could have been nabbing you could have been nabbing he could have been nabbing we could have been nabbing you could have been nabbing they could have been nabbing
Negation
Simple form
I could not nab you could not nab he could not nab we could not nab you could not nab they could not nab
V-ing form
I could not be nabbing you could not be nabbing he could not be nabbing we could not be nabbing you could not be nabbing they could not be nabbing
Perfect
I could not have nabbed you could not have nabbed he could not have nabbed we could not have nabbed you could not have nabbed they could not have nabbed
V-ing perfect
I could not have been nabbing you could not have been nabbing he could not have been nabbing we could not have been nabbing you could not have been nabbing they could not have been nabbing
Interrogative form
Simple form
could I nab? could you nab? could he nab? could we nab? could you nab? could they nab?
V-ing form
could I be nabbing? could you be nabbing? could he be nabbing? could we be nabbing? could you be nabbing? could they be nabbing?
Perfect
could I have nabbed? could you have nabbed? could he have nabbed? could we have nabbed? could you have nabbed? could they have nabbed?
V-ing perfect
could I have been nabbing? could you have been nabbing? could he have been nabbing? could we have been nabbing? could you have been nabbing? could they have been nabbing?
Interro-negative form
Simple form
could I not nab? could you not nab? could he not nab? could we not nab? could you not nab? could they not nab?
V-ing form
could I not be nabbing? could you not be nabbing? could he not be nabbing? could we not be nabbing? could you not be nabbing? could they not be nabbing?
Perfect
could I not have nabbed? could you not have nabbed? could he not have nabbed? could we not have nabbed? could you not have nabbed? could they not have nabbed?
V-ing perfect
could I not have been nabbing? could you not have been nabbing? could he not have been nabbing? could we not have been nabbing? could you not have been nabbing? could they not have been nabbing?