I could pay you could pay he could pay we could pay you could pay they could pay
V-ing form
I could be paying you could be paying he could be paying we could be paying you could be paying they could be paying
Perfect
I could have paid you could have paid he could have paid we could have paid you could have paid they could have paid
V-ing perfect
I could have been paying you could have been paying he could have been paying we could have been paying you could have been paying they could have been paying
Negation
Simple form
I could not pay you could not pay he could not pay we could not pay you could not pay they could not pay
V-ing form
I could not be paying you could not be paying he could not be paying we could not be paying you could not be paying they could not be paying
Perfect
I could not have paid you could not have paid he could not have paid we could not have paid you could not have paid they could not have paid
V-ing perfect
I could not have been paying you could not have been paying he could not have been paying we could not have been paying you could not have been paying they could not have been paying
Interrogative form
Simple form
could I pay? could you pay? could he pay? could we pay? could you pay? could they pay?
V-ing form
could I be paying? could you be paying? could he be paying? could we be paying? could you be paying? could they be paying?
Perfect
could I have paid? could you have paid? could he have paid? could we have paid? could you have paid? could they have paid?
V-ing perfect
could I have been paying? could you have been paying? could he have been paying? could we have been paying? could you have been paying? could they have been paying?
Interro-negative form
Simple form
could I not pay? could you not pay? could he not pay? could we not pay? could you not pay? could they not pay?
V-ing form
could I not be paying? could you not be paying? could he not be paying? could we not be paying? could you not be paying? could they not be paying?
Perfect
could I not have paid? could you not have paid? could he not have paid? could we not have paid? could you not have paid? could they not have paid?
V-ing perfect
could I not have been paying? could you not have been paying? could he not have been paying? could we not have been paying? could you not have been paying? could they not have been paying?