根据材料内容，选择正确答案。

Which Is More Useful?

    Thomas is in Grade Two now. He goes to school from Monday to Friday. After school he must do some housework. He helps his parents on the farm(农场) on Saturdays and Sundays. So he doesn't have any time to play football in the daytime. He often plays with his friends in the moon(月亮).

    It's five in the afternoon. School is over. Thomas goes home and cooks for his family. After dinner he sees his friend Paul near his house and asks him to play football. The boy looks at the sky and sees the moon. Then he asks, "Which is more useful, the sun or the moon?"

    "I think the moon is," says Thomas. "We need light(光线) in the evening, but we can not see the sun, but the moon!"