An old woman walked into a clothes shop. She asked the salesgirl to let her have a look at a new dress on display, but the girl stood still behind the counter, taking no notice of the request. The old woman spoke to the girl again, raising her voice a bit, but still received no answer. The old woman looked closely at the girl and nodded to her, "I am too old to see well." I can't even tell a plastic   model from a real girl." On hearing this, the salesgirl shouted at the old woman, " What? Did you call me a plastic model?" The old woman was greatly surprised. "On, dear me," she said. "The model can speak. Then it must be a robot of a new type." The old woman wanted   _  in the clothes shop.
to buy something to play a joke on someone to look for someone to talk to the girl