r universe and we might help each other. () 56. Seth Shostak and Alexandra t are. A. astronomers B. farmers C. singers () 57. What is the best title for Paragraph 2? A. The Age and Size of Earth B. Why Intelligent Life Might Exist? C. Earth: The Only with Intelligent Life () 58. Why was it hard to look for signs of intelligent life in the universe in the past? A. There were not any smaller s. B. There were not any powerful telescopes. C. The Milky Way didn ’t exist at that time. () 59. Why haven ’t beings from space visited us yet according to Shostak? A. They ’ re afraid of us. B. It’sa long way away. C. They don ’t know how to use radio signals. () 60. What does the underlined phrases “ life forms ” in the last paragraph mean? A. Messages B. Tools C.I ntellige nt beings 参考答案 56-60 ABBBC
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