Question

  If you drop a feather and a hammer ( 鐵錘） , which do you think will hit the ground first?

  On his last moon walk in 1971,Apollo 15's Commander David Scott did his final 21 for the television cameras. Scott was re-creating an experiment  22 by the astronomer Galileo in 1590.

  If you guess that the 23 would hit the ground first,you' re not alone. When Galileo was a boy,everyone 24 that heavier things fell faster. A rock twice as heavy as a potato should fall twice as fast. That's what they 25 in school.

  But Galileo wasn’ t so 26 . So he decided to 27 it. He dropped balls of different 28 from towers and timed how long they took to get to the ground. And he discovered 29 amazing — dropped things fall at the same rate,no matter how 30 they are.

  Why? Falling objects fall 31  the pull of gravity between the object and Earth. And the tremendous (巨大的) force of Earth's gravity is the same whether it's 32 on a feather or a hammer.

  But wait,you say — feathers do fall more 33 than hammers. That's quite true,on Earth — but the 34 is air,not gravity. Air pushes against light feathers enough to hold them up,but it isn't 35 enough to hold up a heavy hammer. This pushing of air 36 people for a long time.

  The moon has no 37 to slow a falling object. But it does have gravity. The moon's gravity is 38than Earth's,since the,moon is smaller. But it's still strong enough for dropping things.

  And sure enough,when Scott let the hammer and the feather drop,they hit the ground 一 exactly 39.

 “Galileo was 40 in his findings/' Scott broadcast. .

21. A. practice   B. interview

   C. experiment   D. flight

22. A. ignored   B. given up

   C. reported   D. thought up

23. A. feather   B. hammer   C. camera   D. rock

24. A. doubted   B. believed

   C. denied   D. forgot

25. A. taught   B. lost   C. learned   D. recorded

26. A. sure   B. sad   C. nervous   D. lucky

27. A. imagine   B. design

   C. name   D. test

28. A. sizes   B. shapes   C. colors   D. weights

29. A. anything   B. nothing

   C. something   D. everything

30. A. soft   B. heavy   C. long   D. beautiful

31. A. instead of   B. because of

   C. in case of   D. in spite of

32. A. depending   B. focusing

   C. pulling   D. relying

33. A. gently   B. steadily

   C. slowly   D. naturally

34. A. reason   B. problem

   C. goal   D. winner

35. A. good   B. big    C. clean   D. strong

36. A. informed   B. fooled

   C. reminded   D. persuaded

37. A. energy   B. time   C. life   D. air

38. A. greater   B. older   C. weaker   D. severer

39. A. alone   B. together

   C. silently   D. loudly

40. A. brave   B. curious

   C. correct   D. humorous

Answer 1

21. C.22. D. 由下文中的 Scott was re-creating  an experiment和介紹伽利略如何開始那個著名的重力實驗可知，1971年，“阿波羅15號”：: 航員斯i特所做的最后一個實驗(experiment) 是由伽利略于1590年想到 (thought up) 的。

23.B. 由下文中的 heavier things fell faster 可知，第三段是對文章首句的回答。此處指大多數(shù) 人認為比哮重的鐵錘(hammer) 會先落地。

24.B. 25.C. 由上文中的you’re not alone可知，： 在伽利略質(zhì)疑這個現(xiàn)象之前，人們都認為I (believed) 較重的物體下落得更快，因為這是 他們從學校學到(learned) 的。

26. A. 27.D. 由伽利略所做的實驗可知，他對人們的認識并不認同(sure) ,于是決定對此進行I 驗證(test) 。

28.D. 由上文可知，人們一直以來認為不同重量 的物體同時下落，重的物體會先落地。伽利略? 對此提出質(zhì)疑，因此他的重力實驗選取了不同重量(weights ) 的球。

29.C. 30.B. 由下文中的 dr?pped things fall at the sa?ie rate可知，伽利略發(fā)現(xiàn)了令人驚奇的 事情(something ) 無論物體多重(heavy ) ，它們下落的速度都一樣。

31.B. 物體和地球之間的地心引力是物體下落的 原因，故用because of。

32.C. 由本空前的 the tremendous force of Earth's gravity is the same可知，地心引力作用 于(pulling) 羽毛或者鐵錘上的力是一樣的。

33. C. 34. A. 由第 33 空后的 That's quite true,on Earth 和第 34 空后的 Air pushes against light feathers ...可知，在地球上，羽毛確實要比鐵鍵 落地慢(slowly ) ,其原因(reason) 在于空氣。

35. D. 由上文中的對比 Air pushes against light feathers enough to hold them up 可知，空氣的浮力役有大(strong) 到可以支撐鐵錘。

36. B. 由第 三段中的 everyone …that heavier i things fell faster可知，長期以來空氣的浮力愚 弄(fooled) 了 人們。

37. D. 由上文探討空氣浮力對物體下落速度的影? 響可知，此處指月球沒有空氣(air) 來減慢下落? 物體的速度。

38. C. 由下文中的 since the moon is smaller. But it's enough for dropping things 可知，月球也有： 地心引力，只不過比地球的地心引力弱： (weaker) 。

39. B. 40. C. 宇航員斯科特在月球上所做重力I 實驗的結果一羽毛和鐵錘完全一起? (together) 落地，證明了伽利略的發(fā)現(xiàn)是正確的(correct) 。