A: What's the weather like? B: I don't know. I just woke up. A: Why don't you look outside? B: Okay. It looks like rain. A: Why do you say that? B: The sky is gray. A: Is it raining right now? B: No. A: How do you know? B: The street isn't wet. A: I have to go shopping today. B: You'd better take an umbrella.