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
What is the talk mainly about?
What is the talk mainly about?
admin
2010-03-19
20
问题
What is the talk mainly about?
The origin of Earth’s moon, the largest moon in the solar system, is still something of a mystery. There are some theories about its origin however. Now, keep in mind that a theory of the moon’s origin has to be consistent with two important facts. The first fact is that the Earth contains a lot of iron, most of it has an iron core. But the moon contains practically no iron. The second fact is that other than the difference in iron content, the moon and Earth are composed of accentually the same minerals, a similarity not shared with any other planet or moon in our solar system.
One of the earliest theories of the moon’s origin, I called it the Capture Theory, proposes that the moon was somehow captured by Earth’s gravitational force. This theory is improbable, however, because it assumes that the moon and Earth formed in different parts of the solar system. If this was true you would expect the moon’s composition to be much different from Earth’s composition, just as all the other planets in the solar system are so different from Earth.
A second theory of the moon’s origin is more promising. It is sometimes referred to as the Mars Theory, because according to this theory, when Earth was still molten, it was struck by a planet about the size of Mars. The impact caused the cores of the two planets to melt together and chunks of Earth’s crust to be thrown out into space. These chunks came together to form the moon. Now, remember, Earth’s crust is low in iron, because the iron is in Earth’s core, but high in various other minerals. This then accounts for why there is little iron but lots of other minerals on the moon.
选项
A、The Moon formed from pieces of Earth’s crust.
B、The Moon was struck by another planet.
C、The Moon’s composition resembles that of Mars.
D、The Moon’s mineral content has changed over time.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/YR9K777K
0
专业英语四级
相关试题推荐
Geographyisstudyoftherelationshipbetweenpeopleandtheland.Geographerscompareandcontrast【C1】______placesontheear
Theinformationsuperhighwaycanbeappliedtothefollowingaspects,exceptwhich?
Ifyouhaveanyquestions,pleasegoandask_________.
ThefamilyisthecenterofmosttraditionalAsians’lives.Manypeopleworryabouttheirfamilieswelfare,reputation,andhono
Thisconversationismainlyabout______
Youcannotbut______hardandsticktoyourgoalsifyoureallywanttosucceed.
Today’strumpetisoneoftheworld’soldestinstruments.Itisreallytheresultofmanycenturiesofdevelopment.Althoughit
Whatdothespeakersmainlydiscuss?
Whataretheymainlytalkingabout?
Satellitecommunicationsaresoup-to-datethatevenwhen______inthemiddleofthePacific,businessmencancontacttheiroff
随机试题
A.淋巴道转移B.血道转移C.直接蔓延D.种植性转移E.椎旁静脉系统的转移胃癌的盆腔转移是
下列呕吐物呈咖啡色的疾病是
甲乙两国是邻国,两国因相邻海域中某岛屿归属产生争端。两国均为联合国会员国,甲曾作出接受联合国国际法院任择强制管辖的声明,乙未作出接受联合国国际法院强制管辖的声明。两国也是《联合国海洋法公约》的缔约国。依国际法相关规则,下列哪些选项是正确的?()
杨某受某厂指派在本县范围内收购茶叶2万斤,厂方提供了介绍信、营业执照副本。杨某收购后未向税务机关纳税。县税务局知悉后即作出决定,杨某须缴纳增值税5000余元。杨某不服,认为自己是接受某厂的指派,与该厂是委托关系,其税款应由厂方缴纳。县税务局未采纳杨某的意见
深圳证券交易所规定使未成交量最小的申报价格为成交价格,若有两个以上使未成交量最小的申报价格符合相关条件的,其平均价为成交价格。( )
当某市场中只存在苹果和梨两种商品.苹果价格上升时人们会减少苹果的购买量而增加梨的购买。此时,苹果与梨这两种商品之间存在:
内隐联想测验是对()进行测量。
关于C/S结构和B/S结构的比较,下列说法中不正确的是______。A)两种结构所描述的都是远程应用访问的模式,从客户端程序向服务器发起请求的方式来看,并没有很大的不同B)从应用模式的发展来看,B/S结构的应用范围越来越广,但C/S仍旧拥有B/S所
I’mtoldthatduringaninternationalgameofchess(国际象棋),manybeautifulmovescouldbemadeonachessboard.Inadecisive【C1】
TodayistheanniversaryofthatafternooninAprilayearagothatIfirstsawthestrangeandappealingdollinthewindowof
最新回复
(
0
)