Conversation (     )1. A. It is a world that moves round our sun.         B. It is a world that has light of its own. C. It is a world that moves round a star.            D. It is a world that is too far for us to see. (     )2. A. Because sometimes we read them in the textbook. B. Because the planets give out light. C. Because we have seen some planets pull their stars to one side while they go round. D. Because the planets are not far away from us. (     )3. A. Barnard's Star always moves quickly for its big size. B. Barnard's Star moves more quickly than any other star up to now. C. Barnard's Star moves more quickly than its planet. D. Barnard's Star sometimes moves slower as we are examining it.