2020年职称英语考试试题：理工类完形填空强化练习题(8)

1、2020 年职称英语考试试题：理工类完形填空强化练习题（8）Earths Inner CoreScientists have long struggled to understand what lies at the planets 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 co

2、ncluded 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 Earths core of molten（熔化了的） iron lies a solidinner core but _ （ 4）_ that core was made of eluded （难

3、倒） her. Other geophysicists quickly determined that Lehmanns inner core was composed mostly _ （5_） iron. Since then, Lehmanns discovery has _（6） _ conventionalEarth science.But now scientists are challenging traditional theory with new and radical _ （7）_. For example, Earths center could actually co

4、ntain 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 bethe oldest fossil _（ 9）_ from the formation of Ea

5、rth,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 Earths center didnt quite melt; it _（11） _ mass asthe planet cooled. The core within a core may be the kern

6、el （核心） that endured. Its presence could change our basic ideas about the _ （12）_ of the planet, Dziewonski says.Dziewonskis idea is tame （温和的） compared to the _ （ 13） _ theories of independent geophysicist J. Marvin Herndon. Earths inner core is made not of iron, he claims, but a_ （ 14）_ of nickel

7、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 ballof the element uranium. Uranium is radioactive. Herndon thinks the uranium releases heat energy as its atoms _（ 15）_ fission-split and crash into one anoth

8、er 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 point2 A create B receive C feel D overcome3 A work B solution C job D patterns4 A whether B what C why D how5 A from B within C of D to6 A followed B dominated C restored D

9、 opposed7 A ideas B demands C phenomena D movements8 A things B acts C methods D records9 A taken B benefited C left D kept10 A after B before C since D when11 A expanded B modified C gained D melted12 A size B origin C structure D shape13 A radical B traditional C classical D conventional14 A system B co