Kate: Hello, David! Is this your fan?
David: No, it isn't. It's Jack's fan.
Kate: Whose umbrella is this?
Jack: It's not my umbrella. It's Mary's.
Kate: Is that your sun cap, Helen?
Helen: Yes, it is. And the camera is mine.
Kate: Let's take them to the beach(沙滩).
David: That sounds good. Let's go!