根据图片提示完成对话。A: Where does the1____________ come from?
B: It comes from the 2____________ .
A: Where does the cloud come from?
B: It comes from the 3____________ .
A: Where does the vapour come from?
B: It comes from the water in the 4____________ .
A: How can the water become vapour?
B: The 5____________shines and the water becomes vapour.
A: Oh, I see.1. rain 2. clouds 3. vapour 4. river 5. sun