A. much easier and even more interesting

　　B. far more exciting and dangerous

　　C. man's final aim

　　D. man's first step

　　26. Which of the following is true?

　　A. Mars is nearer to the earth than the moon.

　　B. The earth is much nearer to the moon than Mars.

　　C. Of all the planets, Mars is the nearest to the earth.

　　D. All the planets are much farther to the earth.

　　27. From the passage, we can guess ________.

　　A. there is life on Mars

　　B. there is no life on Mars

　　C. the atmosphere of Mars is not so dense as that of Venus

　　D. scientists will have little hope to find the answers

　　28. Man can live on under the conditions of _______.

　　A. much too hot surface

　　B. the same pressure as we get on earth

　　C. normal atmosphere as we have on earth

　　D. both B and C

四、完形填空（共20小题；每小题1.5分，满分30分）

　　During World Space Week (October 4th～10th)，you may learn about some of the space's myths. One is: "The Great Wall of China is the only man­made object__29___from space with the naked eye."

　　You might be__30___of this claim, but it's not true. In fact, astronauts say that the Great Wall is just one of many man­made__31___that can be seen from space. From an orbit 217 kilometres___32__the earth, it is__33___to see highways, airports, bridges, dams and even large__34___.

　　Cities can even be seen clearly from the International Space Station ( ISS, 国际空间站)，___35__circles about 400 kilometres above the planet. "You can see the__36___pyramids from space with a pair of binoculars(双筒望远镜). They are a little difficult to___37__with just your eyes，" said Ed Lu, a US astronaut___38___the ISS.

　　"With binoculars you can also see roads, harbours and even very large ___39___ in the ocean. From the moon, astronauts cannot___40___any man­made features on earth and the continents are very hard___41___. On Mars, the earth would appear to the naked eye as___42___but a bright 'star'."___43___what about the Great Wall? "You can see the Great Wall from space," Lu said. "But it's a lot___44___than a lot of other objects. You can only see it in radar images，___45___in ordinary photographs."

　　No one knows who___46___the Great Wall story. The earliest reference to it comes in a book by a US writer Richard Halliburton, published in 1938. He wrote, "Astronomers say that the Great Wall is the only man­made thing on our planet visible to the human eye from the moon."

　　Halliburton's books__47____quite well during the first half of the 20th century. So, if he didn't___48___the story himself, he certainly spread it widely.

　　29. A. invisible B. visible C. acceptable D. unacceptable

　　30. A. proud B. thankful C. strange D. surprised

　　31. A. barriers B. sights C. buildings D. objects

　　32. A. on B. under C. across D. above

　　33. A. possible B. suitable C. unlikely D. interesting

　　34. A. animals B. insects C. vehicles D. birds

　　35. A. that B. which C. where D. whose

　　36. A. Egyptian B. European C. Chinese D. American

37. A. find out B. pick out C. pick up D. take up