David: I want to take some photos in the park, but I can't find my camera. Where is it, mum? Mum: Is it on the computer? David: No, it isn't. It was there yesterday (昨天).Mum: Ah, I see. It's near the computer. David: Thanks. I need some films. Where are they? Mum: They are in the desk. David: I've got it. But where's my bag? It was on the chair a moment ago. Mum: It's on your bed. Can you see it? David: Yes. Bye, mum. 1. What does David want to do in the park? 2. Where is the camera? 3. Where are the films? 4. Is David's bag on the chair?