--When did the World Exposition(世博会) in Shanghai begin? --The Expo began ________ May 1, 2010.
She is _____ friend.
----_____ is this dress? ---- It’s mine.
. ---- Is the letter yours? ---- No, it’s not mine. It’s_____.
----What color is _____ hair? ----I think ______ black.
---What are these ? --- ______ are pens.