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 couldn't tee you couldn't tee she couldn't tee we couldn't tee you couldn't tee they couldn't tee
V-ing form
I couldn't be teeing you couldn't be teeing she couldn't be teeing we couldn't be teeing you couldn't be teeing they couldn't be teeing
Perfect
I couldn't have teed you couldn't have teed she couldn't have teed we couldn't have teed you couldn't have teed they couldn't have teed
V-ing perfect
I couldn't have been teeing you couldn't have been teeing she couldn't have been teeing we couldn't have been teeing you couldn't have been teeing they couldn't 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
couldn't I tee? couldn't you tee? couldn't she tee? couldn't we tee? couldn't you tee? couldn't they tee?
V-ing form
couldn't I be teeing? couldn't you be teeing? couldn't she be teeing? couldn't we be teeing? couldn't you be teeing? couldn't they be teeing?
Perfect
couldn't I have teed? couldn't you have teed? couldn't she have teed? couldn't we have teed? couldn't you have teed? couldn't they have teed?
V-ing perfect
couldn't I have been teeing? couldn't you have been teeing? couldn't she have been teeing? couldn't we have been teeing? couldn't you have been teeing? couldn't they have been teeing?