this key is your mother’s.

-Is this key? -No, that one is key.

A. my, her B. your, my C. her, his

     this key is your mother’s.

A.May         B.Maybe        C.May be          D.Can

---Is this key ________?

--No, it isn’t. It’s ___________.

A．your, John                             B．your, John’s

C．yours, John                            D．yours, John’s

---Is this key ________?
--No, it isn’t. It’s ___________.