David: We have to buy this 100x71 alu frame
David: For this poster you got from my sister
Lizzy: Yeah. Have you decided where will we hang it? 
David: I think over the stairs will be perfect.
David: Ok. I'll stop by the supermarket. Maybe I'll find nice frame there.
Lizzy: Kk.
David and Lizzy need to buy a frame for the poster Lizzy got from David's sister.