I could tee you could tee she could tee we could tee you could tee they could tee
V-ing form
I could be teeing you could be teeing she could be teeing we could be teeing you could be teeing they could be teeing
Perfect
I could have teed you could have teed she could have teed we could have teed you could have teed they could have teed
V-ing perfect
I could have been teeing you could have been teeing she could have been teeing we could have been teeing you could have been teeing they could have been teeing
Negation
Simple form
I could not tee you could not tee she could not tee we could not tee you could not tee they could not tee
V-ing form
I could not be teeing you could not be teeing she could not be teeing we could not be teeing you could not be teeing they could not be teeing
Perfect
I could not have teed you could not have teed she could not have teed we could not have teed you could not have teed they could not have teed
V-ing perfect
I could not have been teeing you could not have been teeing she could not have been teeing we could not have been teeing you could not have been teeing they could not have been teeing
Interrogative form
Simple form
could I tee? could you tee? could she tee? could we tee? could you tee? could they tee?
V-ing form
could I be teeing? could you be teeing? could she be teeing? could we be teeing? could you be teeing? could they be teeing?
Perfect
could I have teed? could you have teed? could she have teed? could we have teed? could you have teed? could they have teed?
V-ing perfect
could I have been teeing? could you have been teeing? could she have been teeing? could we have been teeing? could you have been teeing? could they have been teeing?
Interro-negative form
Simple form
could I not tee? could you not tee? could she not tee? could we not tee? could you not tee? could they not tee?
V-ing form
could I not be teeing? could you not be teeing? could she not be teeing? could we not be teeing? could you not be teeing? could they not be teeing?
Perfect
could I not have teed? could you not have teed? could she not have teed? could we not have teed? could you not have teed? could they not have teed?
V-ing perfect
could I not have been teeing? could you not have been teeing? could she not have been teeing? could we not have been teeing? could you not have been teeing? could they not have been teeing?