I could greet you could greet he could greet we could greet you could greet they could greet
V-ing form
I could be greeting you could be greeting he could be greeting we could be greeting you could be greeting they could be greeting
Perfect
I could have greeted you could have greeted he could have greeted we could have greeted you could have greeted they could have greeted
V-ing perfect
I could have been greeting you could have been greeting he could have been greeting we could have been greeting you could have been greeting they could have been greeting
Negation
Simple form
I could not greet you could not greet he could not greet we could not greet you could not greet they could not greet
V-ing form
I could not be greeting you could not be greeting he could not be greeting we could not be greeting you could not be greeting they could not be greeting
Perfect
I could not have greeted you could not have greeted he could not have greeted we could not have greeted you could not have greeted they could not have greeted
V-ing perfect
I could not have been greeting you could not have been greeting he could not have been greeting we could not have been greeting you could not have been greeting they could not have been greeting
Interrogative form
Simple form
could I greet? could you greet? could he greet? could we greet? could you greet? could they greet?
V-ing form
could I be greeting? could you be greeting? could he be greeting? could we be greeting? could you be greeting? could they be greeting?
Perfect
could I have greeted? could you have greeted? could he have greeted? could we have greeted? could you have greeted? could they have greeted?
V-ing perfect
could I have been greeting? could you have been greeting? could he have been greeting? could we have been greeting? could you have been greeting? could they have been greeting?
Interro-negative form
Simple form
could I not greet? could you not greet? could he not greet? could we not greet? could you not greet? could they not greet?
V-ing form
could I not be greeting? could you not be greeting? could he not be greeting? could we not be greeting? could you not be greeting? could they not be greeting?
Perfect
could I not have greeted? could you not have greeted? could he not have greeted? could we not have greeted? could you not have greeted? could they not have greeted?
V-ing perfect
could I not have been greeting? could you not have been greeting? could he not have been greeting? could we not have been greeting? could you not have been greeting? could they not have been greeting?