Li Lei：（Excuse ）me,Tom.Do you have（an ）eraser?
Tom：Sorry.I（don't ）.
Li Lei:Do you think David ( has ) one?
Tom：I think ( so ).You can ask ( him ).
Li Lei:David ,may I have ( your ) eraser,please?
David:Sorry,Lucy has ( my ) eraser.Please go and ask her.
Li Lei:Excuse me,Lucy.May I ( have ) David's eraser?
Lucy:CXertainly.Here you are.But you must give it to him soon.
Li Lei:OK.( Thanks ) a lot.