首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、The cutting of diamonds needs to have some changes. B、The environment of making diamonds has changed. C、The composition of roc
A、The cutting of diamonds needs to have some changes. B、The environment of making diamonds has changed. C、The composition of roc
admin
2014-05-30
88
问题
Diamonds are the hardest substance known on Earth and they make sparkling jewelry as well as saw blades that can cut through pretty much anything.
Recently, geologists studying diamonds have identified the ages of thousands of diamonds from Southern Africa, where the mineral is most abundant. Their research found that there were only three times in Earth’s history when diamonds were made and that Earth no longer makes diamonds like it used to. "Something was different then. Perhaps the planet was hotter on the inside, or the composition of the rocks was subtly different. Whatever it was it has changed now," stated Steve Shirey, of the Carnegie Institution in Washington, D.C., one of the project researchers.
The oldest diamonds were made 3.3 billion years ago when Earth was relatively young. The second time diamonds formed was 2.9 billion years ago. Small bits of rock within those diamonds, called impurities, indicate that they probably formed from rocks laid down in a shallow sea suggesting that the carbon that made the diamonds probably came from the remains of ancient sea life. The youngest diamonds on Earth are 1.2 billion years old although a few smaller diamonds are about 100 million years old.
Some people like diamonds because they are pretty, rare, or expensive but Dr. Steve Shirey has a different perspective. "I think of diamonds," he said, "as being tiny time capsules that encase a little piece of rock protecting it for billions of years and providing us with a unique window on ancient times."
19. What does the speaker tell us about diamonds?
20. What does the speaker want to convey by the remarks of Steve Shirey?
21. According to the speaker, when were the youngest diamonds made?
选项
A、The cutting of diamonds needs to have some changes.
B、The environment of making diamonds has changed.
C、The composition of rocks is the same as it used to.
D、The demand for diamonds has increased recently.
答案
B
解析
Steve Shirey猜测“以前钻石形成时,地球的内部可能很热,岩石的构造可能有些不一样,但是不管怎样,现在一切都已经改变了。”地球温度和岩石构造都属于钻石形成的环境。故B项正确。
转载请注明原文地址:https://kaotiyun.com/show/oi17777K
0
大学英语六级
相关试题推荐
Apunctualpersonisinthehabitofdoingeverythingatthepropertimeandisneverlateinkeepinganappointment.Theunpunc
A、Makeacalltoherbrother.B、Buyabookforherbrother.C、Checkoutthelist.D、Askthemanaquestion.A女士想给弟弟买几本书,却又不知道买什么
Somepeople’searsproducewaxlikebusylittlebees.Thiscanbeaproblemeventhoughearwax(耳垢)appearstoserveanimportant
A、Customerandsalesperson.B、Teacherandstudent.C、Bossandsecretary.D、Guestandwaitress.C关键是听到男士让女士复印20份并送给执行总裁以及各部门经理,女士
Forthispart,youareallowed30minutestowriteashortessayentitledHowtoBroadenOurKnowledge?Youshouldwriteatleas
A、Heisweakinhealth.B、Hehascaughtacold.C、Heisverycareless.D、Heisseriouslyill.A听音时要抓住关键词组alittleundertheweat
TheFutureIsAnotherCountryAcoupleofmonthsorsoafterbecomingBritain’sprimeminister,DavidCameronwantedafewt
Apparentlyeveryoneknowsthatglobalwarmingonlymakesclimatemoreextreme.Ahot,drysummerhastriggeredanotherfloodof
Manybankersmaybeworriedaboutwhethersomefancyproductdreamedupmightyetleadtoavisitfromthepolice.DanielDantas
A、Themanisopposedtodrinking.B、Lastyear’sChristmasdinnerpartywasasuccess.C、Thewomandoesnotwanttogotothisye
随机试题
法律文书在制作中主旨和材料是()
女性,48岁。5年来渐进性劳累后心悸、气短,1年来加重,曾有夜间憋醒,需坐起后缓解,既往有关节痛史。检查发现心脏扩大,可闻及杂音,胸片显示如下。(2013年第94题)该患者可能闻及的心脏杂音是
质地致密、坚实,宜切薄片的药材是
男性,50岁,上腹不适,食欲缺乏3个月,黄疸进行性加重1个月。检查:皮肤巩膜明显黄染,肝右肋下似可扪及增大的胆囊。化验:血胆红素260,5μ×mol/L尿胆红素阳性。最可能的诊断是( )
【2003年第18题】如图3-233所示,连续梁的中间支座可产生哪几种反力?
有些项目可能在五至十年后还要进行再评价,以确定项目对()的真实影响。
下列施工项目中,属于经批准可以采用邀请招标方式发包的有()工程项目。
我国《保险法》所规范的是()。[2005年真题]
与_______共同构成中国诗歌传统源头的《楚辞》,主要作者是因谗去国、被流放到蛮荒之地的屈原,他用“_______”这一著名诗句,表现了岁月蹉跎、时不我待的恐惧。文中画横线部分应依次填入()。
Alargepartofeffectiveleadershipisdependentonsomethingcalled"style".Butstyleisdifficulttoteach,andwhatmakes
最新回复
(
0
)