读对话，按要求做题
It's raining. Ann meets Little Water Drop. She's talking with him.
Ann: Hi, where do you come from, Little Water Drop?
Little Water Drop: I come from the sea.
Ann: Oh，that's far from here.
Little Water Drop: Yes. I come here in a cloud. I fly over rivers and mountains.
Ann: Now you fall down here. How do you go back to the sky?
Little Water Drop: The sun shines and shines. I get hot. Then I go up to the sky. It's cool there. I am in a cloud.
Ann: Do you feel happy?
Little Water Drop: Yes, I do. I can help people. I am useful. People use water to wash clothes and vegetables, cook food, wash clothes, make drinks and so on. Farmers use water to grow crops and firemen use water to put out fires.
pC（g）＋qD（g），