I could stroke you could stroke he could stroke we could stroke you could stroke they could stroke
V-ing form
I could be stroking you could be stroking he could be stroking we could be stroking you could be stroking they could be stroking
Perfect
I could have stroked you could have stroked he could have stroked we could have stroked you could have stroked they could have stroked
V-ing perfect
I could have been stroking you could have been stroking he could have been stroking we could have been stroking you could have been stroking they could have been stroking
Negation
Simple form
I could not stroke you could not stroke he could not stroke we could not stroke you could not stroke they could not stroke
V-ing form
I could not be stroking you could not be stroking he could not be stroking we could not be stroking you could not be stroking they could not be stroking
Perfect
I could not have stroked you could not have stroked he could not have stroked we could not have stroked you could not have stroked they could not have stroked
V-ing perfect
I could not have been stroking you could not have been stroking he could not have been stroking we could not have been stroking you could not have been stroking they could not have been stroking
Interrogative form
Simple form
could I stroke? could you stroke? could he stroke? could we stroke? could you stroke? could they stroke?
V-ing form
could I be stroking? could you be stroking? could he be stroking? could we be stroking? could you be stroking? could they be stroking?
Perfect
could I have stroked? could you have stroked? could he have stroked? could we have stroked? could you have stroked? could they have stroked?
V-ing perfect
could I have been stroking? could you have been stroking? could he have been stroking? could we have been stroking? could you have been stroking? could they have been stroking?
Interro-negative form
Simple form
could I not stroke? could you not stroke? could he not stroke? could we not stroke? could you not stroke? could they not stroke?
V-ing form
could I not be stroking? could you not be stroking? could he not be stroking? could we not be stroking? could you not be stroking? could they not be stroking?
Perfect
could I not have stroked? could you not have stroked? could he not have stroked? could we not have stroked? could you not have stroked? could they not have stroked?
V-ing perfect
could I not have been stroking? could you not have been stroking? could he not have been stroking? could we not have been stroking? could you not have been stroking? could they not have been stroking?