第5题: [单项选择]Questions 11 to 13 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. This passage is about ______. A. the sun B. light and heat C. the source of nuclear energy D. X-ray 参考答案:C 答案解析:[听力原文] 11-13 A summary of the physical and chemical nature of life must begin, not on the Earth