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:mertanly.here you are.but you must give it back to him soon.
li lei:ok.Thanks a lot.