首页 > 教育 > 外语考试 > 职称英语 > 理工类 > 正文
职称英语考试理工类完形填空精选习题(9)
2013-04-07 17:34:47    发布(作)者:    来源:     我来说两句      
收藏    我要投稿

核心提要:   Earth's Inner Core  Scientists have long struggled to understand what lies at the planet's center. Direct observation of its center is impossible...


  Earth's Inner Core

  Scientists have long struggled to understand what lies at the planet's center. Direct observation of its center is impossible, so researchers must (1) to other evidence.

  In 1889, a German scientist detected a severe earthquake in Japan. Geophysicists concluded that shock waves (2) jolts (晃动) from one side of Earth through the center to the other side. Then in 1936, Danish geophysicist Inge Lehmann studied the waves' (3) to determine that within Earth's core of molten (熔化了的) iron lies a solid inner core - but (4) that core was made of eluded (难倒) her. Other geophysicists quickly determined that Lehmann's inner core was composed mostly (5) iron. Since then, Lehmann's discovery has (6) conventional Earth science.

  But now scientists are challenging traditional theory with new and radical (7). For example, Earth's center could actually contain an "inner core within the inner core," claim Ishii and colleague Adam Dziewonski.

  Analyzing hundreds of thousands of earthquake wave (8), they maintain that the inner core has at its heart a tiny, even more solid sphere (球体). This sphere "may be the oldest fossil (9) from the formation of Earth," says Dziewonski.

  Dziewonski and Ishii speculate that shortly (10) Earth formed around 4.8 billion years ago, a giant asteroid (小行星) smashed into the young planet and nearly melted it. But Earth's center didn't quite melt; it (11) mass as the planet cooled. The core within a core may be the kernel (核心) that endured. "Its presence could change our basic ideas about the (12) of the planet," Dziewonski says.

  Dziewonski's idea is tame (温和的) compared to the (13) theories of independent geophysicist J. Marvin Herndon. Earth's inner core is made not of iron, he claims, but a (14) of nickel and silicon. Herndon has a truly revolutionary notion: Within the nickel silicide (硅化物) inner core is also an "inner" inner core - an 8 km-wide ball of the element uranium. Uranium is radioactive. Herndon thinks the uranium releases heat energy as its atoms (15) fission-split and crash into one another in a chain reaction. In other words, we may live on top of a gigantic, "natural" nuclear power plant.

  1 A try B leave C turn D point

  2 A create B receive C feel D overcome

  3 A work B solution C job D patterns

  4 A whether B what C why D how

  5 A from B within C of D to

  6 A followed B dominated C restored D opposed

  7 A ideas B demands C phenomena D movements

  8 A things B acts C methods D records

  9 A taken B benefited C left D kept

  10 A after B before C since D when

  11 A expanded B modified C gained D melted

  12 A size B origin C structure D shape

  13 A radical B traditional C classical D conventional

  14 A system B copy C model D compound

  15 A charge B last C experience D show

  参考答案:

  1. C 2. A 3. D 4. B 5. C

  6. B 7. A 8. D 9. C 10. A

  11. C 12. B 13. A 14. D 15. C

职称英语考试理工类完形填空精选习题(3)职称英语考试理工类完形填空精选习题(2) 职称英语考试理工类完形填空精选习题(1)
关键字:职称英语 考试 理工类

点击复制链接 与好友分享!回本站首页
分享到:
您对本文章有什么意见或着疑问吗?请到论坛讨论您的关注和建议是我们前行的参考和动力  
上一篇:职称英语考试理工类完形填空精选习题(8)
下一篇:职称英语考试理工类完形填空精选习题(10)
相关文章
图文推荐
美图推荐
热文推荐