職稱(chēng)英語(yǔ)完形填空練習(xí)

時(shí)間：2024-07-27 15:44:01 學(xué)人智庫(kù) 我要投稿

　　Earths Inner Core

職稱(chēng)英語(yǔ)完形填空練習(xí)

　　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.

[職稱(chēng)英語(yǔ)完形填空練習(xí)]相關(guān)文章：

1.職稱(chēng)英語(yǔ)完形填空練習(xí)精選

2.2017職稱(chēng)英語(yǔ)考試完形填空真題練習(xí)

3.2017年職稱(chēng)英語(yǔ)完形填空練習(xí)（含答案）

4.2015職稱(chēng)英語(yǔ)《理工類(lèi)》完形填空模擬練習(xí)

5.職稱(chēng)英語(yǔ)綜合類(lèi)完形填空練習(xí)題及答案

6.2016年職稱(chēng)英語(yǔ)完形填空練習(xí)題

7.職稱(chēng)英語(yǔ)綜合B級(jí)完形填空練習(xí)

8.職稱(chēng)英語(yǔ)綜合類(lèi)完形填空練習(xí)及答案

9.2014職稱(chēng)英語(yǔ)《理工類(lèi)》完形填空練習(xí)1

10.職稱(chēng)英語(yǔ)完形填空試題及答案

【職稱(chēng)英語(yǔ)完形填空練習(xí)】相關(guān)文章：