Make a diaogue about preparations for the coming school festival

Make a diaogue about preparations for the coming school festival
sister:have you bought......................?
lan:..................where are you going?
sister:to the market. I need.................
lan:could you by me......................?
sister:sure.
lan:I need..........................
sister:ok. I will buy you every thing you need.
lan:...............................................
sister:.....................................................