抄写句子,补全对话。 A. Is that the wall? B. Is that a picture? C. Is this a TV? D. What's on it? A: Is this a teacher's desk? B: Yes, it is. A: 1. B: Let's go and have a look. A: 2. B: No, it's a computer. A: 3. B: No, it's a map. A: 4. B: No, that's the floor.