Tom and his classmate，Jerry，are talking about the sun and the moon. Jerry asks，"Which of them is more useful?”

　　汤姆和他的同学杰瑞正在讨论太阳和月亮的话题。杰瑞问:“它们中哪一个更有用?”

　　Tom replied，"Of course，the moon. The moon is in the sky when it is dark，but the sun is in the sky in the daytime when nobody needs it.”

　　汤姆回答道:“当然是月亮。月亮在天黑的时候挂在天空。可是太阳是在白天谁也不需要它的时候出现在天空。”