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    Do you know about the sun, the moon or the earth? Let me tell you. The sun is a star. It is big and bright. It is hot. And it gives us light and heat(光和热量). We need the sun. Animals and plants both need it. The moon is a satellite(卫星). It goes around (围绕...转) the earth. On the moon there is no water or air(空气). So no people live on the moon. The earth is a planet(行星). It goes around the sun. It is our home. We live on the earth. So we should love our home-the earth.