职称英语理工类B级完形填空指导练习(2)

　　Earths Inner Core

　　Scientists have long struggled to understand what lies at the planets center, Direct observation of its center is impossible，so researchers must_____to other evidence.

　　In 1889，a German scientist detected a severe earthquake in Japan.Geophysicists concluded that shock waves_____joltsfrom one side of Earth through the center to the other side.Then in 1936，Danish geophysicist Inge Lehmann studied the waves______ to determine that within Earths core of molteniron lies a solid inner core-but_____ that core was made of eludedher.Other geophysicists quickly determined that Lehmanns inner core was composed mostly_____iron. Since then， Lehmanns discovery has_____conventional Earth science.

　　But now scientists are challenging traditional theory with new and radical _____ For example，Earths center could actually contain aninner core within the inner core，claim Ishii and colleague Adam Dziewonski.

　　Analyzing hundreds of thousands of earthquake wave _____,they maintain that the inner core has at its heart a tiny, even more solid sphere . This spheremay be the oldest fossil____from the formation of Earth，says Dziewonski.

　　Dziewonski and Ishii speculate that shortly_____ Earth formed around 4.8billion years ago，a giant asteroidsmashed into the young planet and nearly melted it. But Earths center didnt quite melt;it______mass as the planet cooled. The core within a core may be the kernelthat endured.Its presence could change our basic ideas about the_____ of the planet，Dziewonski says idea is tamecompared to the_____theories of independent geophysicist J.Marvin Herndon.Earths inner core is made not of iron，he claims but a_____of nickel and silicon Hemdon has a truly revolutionary notion：Within the nickel silicideinner core is also aninnerinner core-an 8 km-wide ball of the element uranium.Uranium is radioactive.Hemdon thinks the uranium releases heat energy as its atoms_____fission-split and crash into another in a chain reaction. In other words,we may live on top of a gigantic, naturalnuclear power plant.

　　51 A try B leave C turn D point

　　52 A create B receive C feel D overcome

　　53 A work B solution C job D patterns

　　54 A whether B what C why D how

　　55 A from B within C of D to

　　56 A followed B dominated C restored D opposed

　　57 A ideas B demands C phenomena D movements

　　58 A things B acts C methods D records

　　59 A taken B benefited C left D kept

　　60 A after B before C since D when

　　61 A expanded B modified C gained D melted

　　62 A size B origin C structure D shape

　　63 A radical B traditional C classical D conventional

　　64 A system B copy C model D compound

　　65 A charge B last C experience D show

　　答案:

　　51 C turn to other evidence：寻求其他证据。Tum to属固定搭配。

　　52 A create jolts：造成震动。其他几个选项意思不符。

　　53 D wayespatterns：波浪的形状。科学家通过研究震波的形状了解地球的情况。

　　54 B 此处的意思是地心是由什么构成的难倒了她。这里应使用what构成名词性从旬，作主语。

　　55 C compose of：由组成。固定短语。

　　56 B dominate：占统治地位，支配。Lehamann的发现在传统地球科学领域占统治地位。

　　57 A 此处的意思是：现在的科学家正用新的、激进的观点挑战传统的理论。本题只有填ideas才符合本句的意思。

　　58 D 此处填records，本句的意思是：通过分析数十万次地震波的记录，他们认为。其他几个选项与句意不符。

　　59 C left：留下来的。此处的意思是：这一球体可能是地球形成时留下来的最古老的化石。

　　60 A 依据上下文，应用afte~句子意思才讲得通。

　　61 C gain：获取。gained mass as the planet cooled：在星球变冷的过程中，它逐渐获得了质量。

　　62 B 本文主要谈地球起源问题，故此处应填ongm.

　　63 A 本句前面出现的一个词是tame，与之对应，应该是radical.

　　64 D nickel和silicon的混合物，compound：混合物。

　　65 C fission-split：裂变。经历裂变，用动词experience.