I could rob you could rob he could rob we could rob you could rob they could rob
V-ing form
I could be robbing you could be robbing he could be robbing we could be robbing you could be robbing they could be robbing
Perfect
I could have robbed you could have robbed he could have robbed we could have robbed you could have robbed they could have robbed
V-ing perfect
I could have been robbing you could have been robbing he could have been robbing we could have been robbing you could have been robbing they could have been robbing
Negation
Simple form
I could not rob you could not rob he could not rob we could not rob you could not rob they could not rob
V-ing form
I could not be robbing you could not be robbing he could not be robbing we could not be robbing you could not be robbing they could not be robbing
Perfect
I could not have robbed you could not have robbed he could not have robbed we could not have robbed you could not have robbed they could not have robbed
V-ing perfect
I could not have been robbing you could not have been robbing he could not have been robbing we could not have been robbing you could not have been robbing they could not have been robbing
Interrogative form
Simple form
could I rob? could you rob? could he rob? could we rob? could you rob? could they rob?
V-ing form
could I be robbing? could you be robbing? could he be robbing? could we be robbing? could you be robbing? could they be robbing?
Perfect
could I have robbed? could you have robbed? could he have robbed? could we have robbed? could you have robbed? could they have robbed?
V-ing perfect
could I have been robbing? could you have been robbing? could he have been robbing? could we have been robbing? could you have been robbing? could they have been robbing?
Interro-negative form
Simple form
could I not rob? could you not rob? could he not rob? could we not rob? could you not rob? could they not rob?
V-ing form
could I not be robbing? could you not be robbing? could he not be robbing? could we not be robbing? could you not be robbing? could they not be robbing?
Perfect
could I not have robbed? could you not have robbed? could he not have robbed? could we not have robbed? could you not have robbed? could they not have robbed?
V-ing perfect
could I not have been robbing? could you not have been robbing? could he not have been robbing? could we not have been robbing? could you not have been robbing? could they not have been robbing?