20．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 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 a time．Scientists are looking for any signal that stands out from the background noise．
Of the 200 billion stars in the Milky Way galaxy，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 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．
However，many scientists wonder whether intelligent life exists on other planets．Some believe that twenty years of searching without any intelligible messages shows that no one is out there．They say that the evolution of intelligence comparable to ours is unlikely．
Other scientists believe that our search hasn't been long enough to rule out the possibility that intelligent life exists in our galaxy．Although our sun family is only about five billion years old，our galaxy is about 20billion years old．In that time，some scientists think it is likely that civilization much more advanced than ours have developed．Perhaps these civilizations send us no signals； perhaps we have not recognized the signals they have sent us．If we hope to find intelligent life，these scientists believe that we have to keep looking．
32．According to the passage，how many planets in our galaxy might be inhabitable？A
A.5 billion．
B.10 billion．
C.15 billion．
D.100 billion
33．The first paragraph in this passage is mainly aboutA．
A．the ways scientists are looking for signs of life on other planets
B．the reasons why scientists are looking for signs of life on other planets
C．the possibilities of finding out signs of life on other planets
D．the difficulties scientists have looking for signs of life on other planets
34．The underlined word"monitor"in the passage means"D"．
A．change
B．control
C．conduct
D．check
35．Which of these statements is true based on the information in the passage？C
A．The earth is one of the oldest planets in our galaxy．
B．Most scientists believe that there is intelligent life on other planets．
C．All the scientists won't give up searching for signs of life on other planets．
D．Scientists don't believe that there might be life on other planets．
分析 文章大意：本文討論了外太空是否存在生命，科學(xué)家們嘗試了多種辦法探尋外星生命，但都沒有得到回應(yīng)，也有科學(xué)家認(rèn)為外太空不可能存在生命．
解答 答案：32-35 AADC
詳解：
32．A，數(shù)據(jù)推算題，根據(jù)第三段前兩句Of the 200 billion stars in the Milky Way galaxy，scientists find that five percent are like our sun．Perhaps half of them have a planet like earth．可知在銀河系里有200billion顆恒星，其中5%的恒星像我們的太陽，也就是說10billion顆像我們的太陽，其中一半有像地球一樣的行星，那么也就是5billion顆像地球一樣的行星，故選A．
33．A，主旨大意題，根據(jù)本段第二句Most of these searches have been done over the radio．和最后一句Scientists also have sent radio and television messages on spaceships traveling through space，on the chance that someone may be receptive to such messages．可知本段主要介紹了科學(xué)家們通過向外太空發(fā)送無線電信號的方式來尋找外星生命，故選 A．
34．D，詞義猜測題，根據(jù)本句Using a computer，they will be able to monitor more than eight channels at a time，科學(xué)家們向外太空發(fā)送無線電信號后，使用計算機對這些信號監(jiān)控，希望能夠捕捉到外星生命的痕跡，所以詞義為check，選D．
35．C，事實細(xì)節(jié)題，根據(jù)文章第一段，F(xiàn)or more than twenty years，scientists have been searching for signs of life on other planets，說明科學(xué)家們不會放棄在其他星球?qū)ふ疑E象．
點評 閱讀理解解題步驟：
首先對原文材料迅速瀏覽，掌握全文的主旨大意．因為閱讀理解題一般沒有標(biāo)題，所以，速讀全文，抓住中心主旨很有必要，在速讀的過程中，應(yīng)盡可能多地捕獲信息材料．
其次，細(xì)讀題材，各個擊破．掌握全文的大意之后，細(xì)細(xì)閱讀每篇材料后的問題，弄清每題要求后，帶著問題，再回到原文中去尋找、捕獲有關(guān)信息．
要善于抓住每段的主題句，閱讀時，要有較強的針對性．對于捕獲到的信息，要做認(rèn)真分析，仔細(xì)推敲，理解透徹，只有這樣，針對題目要求，才能做到穩(wěn)、準(zhǔn)．
