I could tiptoe you could tiptoe she could tiptoe we could tiptoe you could tiptoe they could tiptoe
V-ing form
I could be tiptoing you could be tiptoing she could be tiptoing we could be tiptoing you could be tiptoing they could be tiptoing
Perfect
I could have tiptoed you could have tiptoed she could have tiptoed we could have tiptoed you could have tiptoed they could have tiptoed
V-ing perfect
I could have been tiptoing you could have been tiptoing she could have been tiptoing we could have been tiptoing you could have been tiptoing they could have been tiptoing
Negation
Simple form
I could not tiptoe you could not tiptoe she could not tiptoe we could not tiptoe you could not tiptoe they could not tiptoe
V-ing form
I could not be tiptoing you could not be tiptoing she could not be tiptoing we could not be tiptoing you could not be tiptoing they could not be tiptoing
Perfect
I could not have tiptoed you could not have tiptoed she could not have tiptoed we could not have tiptoed you could not have tiptoed they could not have tiptoed
V-ing perfect
I could not have been tiptoing you could not have been tiptoing she could not have been tiptoing we could not have been tiptoing you could not have been tiptoing they could not have been tiptoing
Interrogative form
Simple form
could I tiptoe? could you tiptoe? could she tiptoe? could we tiptoe? could you tiptoe? could they tiptoe?
V-ing form
could I be tiptoing? could you be tiptoing? could she be tiptoing? could we be tiptoing? could you be tiptoing? could they be tiptoing?
Perfect
could I have tiptoed? could you have tiptoed? could she have tiptoed? could we have tiptoed? could you have tiptoed? could they have tiptoed?
V-ing perfect
could I have been tiptoing? could you have been tiptoing? could she have been tiptoing? could we have been tiptoing? could you have been tiptoing? could they have been tiptoing?
Interro-negative form
Simple form
could I not tiptoe? could you not tiptoe? could she not tiptoe? could we not tiptoe? could you not tiptoe? could they not tiptoe?
V-ing form
could I not be tiptoing? could you not be tiptoing? could she not be tiptoing? could we not be tiptoing? could you not be tiptoing? could they not be tiptoing?
Perfect
could I not have tiptoed? could you not have tiptoed? could she not have tiptoed? could we not have tiptoed? could you not have tiptoed? could they not have tiptoed?
V-ing perfect
could I not have been tiptoing? could you not have been tiptoing? could she not have been tiptoing? could we not have been tiptoing? could you not have been tiptoing? could they not have been tiptoing?