Question

  If you drop a feather and a hammer ( 铁锤） , 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和介绍伽利略如何开始那个著名的重力实验可知，1971年，“阿波罗15号”：: 航员斯i特所做的最后一个实验(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，第三段是对文章首句的回答。此处指大多数 人认为比哮重的铁锤(hammer) 会先落地。

24.B. 25.C. 由上文中的you’re not alone可知，： 在伽利略质疑这个现象之前，人们都认为I (believed) 较重的物体下落得更快，因为这是 他们从学校学到(learned) 的。

26. A. 27.D. 由伽利略所做的实验可知，他对人们的认识并不认同(sure) ,于是决定对此进行I 验证(test) 。

28.D. 由上文可知，人们一直以来认为不同重量 的物体同时下落，重的物体会先落地。伽利略? 对此提出质疑，因此他的重力实验选取了不同重量(weights ) 的球。

29.C. 30.B. 由下文中的 dr?pped things fall at the sa?ie rate可知，伽利略发现了令人惊奇的 事情(something ) 无论物体多重(heavy ) ，它们下落的速度都一样。

31.B. 物体和地球之间的地心引力是物体下落的 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) 羽毛或者铁锤上的力是一样的。

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，羽毛确实要比铁键 落地慢(slowly ) ,其原因(reason) 在于空气。

35. D. 由上文中的对比 Air pushes against light feathers enough to hold them up 可知，空气的浮力役有大(strong) 到可以支撑铁锤。

36. B. 由第 三段中的 everyone …that heavier i things fell faster可知，长期以来空气的浮力愚 弄(fooled) 了 人们。

37. D. 由上文探讨空气浮力对物体下落速度的影? 响可知，此处指月球没有空气(air) 来减慢下落? 物体的速度。

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，只不过比地球的地心引力弱： (weaker) 。

39. B. 40. C. 宇航员斯科特在月球上所做重力I 实验的结果一羽毛和铁锤完全一起? (together) 落地，证明了伽利略的发现是正确的(correct) 。