冲刺2008高考英语模拟试题 (一) 下 (含解析)

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　　For more than twenty years scientists have been searching for signs of life on other planets. Most of these searches have been done over the radio. The hope is that someone in outer space may be trying to get in touch with us. Scientists also have sent radio and television messages on spaceships traveling through space, on the chance that someone may be receptive to such messages.
　　Scientists are using powerful radio telescopes to listen to signals from about 1, 000 stars, all within 100 light years of earth. In addition, they will scan（扫视）the entire sky to “listen” for radio messages from more distant stars. Using a computer, they will be able to monitor more than eight channels at one time. Scientists are looking for any signal they stands out from the background noise.
　　Of the 200 billion stars in the Milky Way galaxy（银河星系）, scientists find that five percent are like our sun. Perhaps half of them have a planet like earth. Such a planet would be a reasonable distance from the star for temperatures to be right for the evolution（进化）of life. Based on the inhabitable（that can be lived in）planets in our galaxy, most scientists agree that chances are likely that one or more of these planets support some life.

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