I could circle you could circle he could circle we could circle you could circle they could circle
V-ing form
I could be circling you could be circling he could be circling we could be circling you could be circling they could be circling
Perfect
I could have circled you could have circled he could have circled we could have circled you could have circled they could have circled
V-ing perfect
I could have been circling you could have been circling he could have been circling we could have been circling you could have been circling they could have been circling
Negation
Simple form
I could not circle you could not circle he could not circle we could not circle you could not circle they could not circle
V-ing form
I could not be circling you could not be circling he could not be circling we could not be circling you could not be circling they could not be circling
Perfect
I could not have circled you could not have circled he could not have circled we could not have circled you could not have circled they could not have circled
V-ing perfect
I could not have been circling you could not have been circling he could not have been circling we could not have been circling you could not have been circling they could not have been circling
Interrogative form
Simple form
could I circle? could you circle? could he circle? could we circle? could you circle? could they circle?
V-ing form
could I be circling? could you be circling? could he be circling? could we be circling? could you be circling? could they be circling?
Perfect
could I have circled? could you have circled? could he have circled? could we have circled? could you have circled? could they have circled?
V-ing perfect
could I have been circling? could you have been circling? could he have been circling? could we have been circling? could you have been circling? could they have been circling?
Interro-negative form
Simple form
could I not circle? could you not circle? could he not circle? could we not circle? could you not circle? could they not circle?
V-ing form
could I not be circling? could you not be circling? could he not be circling? could we not be circling? could you not be circling? could they not be circling?
Perfect
could I not have circled? could you not have circled? could he not have circled? could we not have circled? could you not have circled? could they not have circled?
V-ing perfect
could I not have been circling? could you not have been circling? could he not have been circling? could we not have been circling? could you not have been circling? could they not have been circling?