首页
登录
职称英语
What is the purpose of the talk? [br] [originaltext] There were several imp
What is the purpose of the talk? [br] [originaltext] There were several imp
游客
2024-10-27
30
管理
问题
What is the purpose of the talk? [br]
There were several important discoveries in the early part of the century that helped geologists develop a more accurate picture of the earth’s interior. The first key discovery had to do with seismic waves. Remember, they are the vibrations caused by earthquakes. Well, scientists found that they travel thousands of miles through the earth’s interior. This finding enabled geologists to study the inner parts of the earth.
You see, these studies revealed that these vibrations were of two types: compression or P-waves and shear or S-waves. And researchers found that P-waves travel through both liquids and solids while S-waves travel only through solid matter. In 1906, a British geologist discovered that P-waves slowed down at a certain depth but kept traveling deeper. On the other hand, S-waves either disappeared or were reflected back. So he concluded that the depth marked the boundary between a solid mantle and the liquid core. Three years later, another boundary was discovered, that between the mantle and the earth’s crust.
There are still a lot to be learned about the earth. For instance, geologists know that the core is hot. Evidence of this is the molten lava that flows out of volcanoes. But we are still not sure what the source of the heat is.
选项
A、How deep they are.
B、Where earthquakes form.
C、How hot they are.
D、What purpose they serve.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3819837.html
相关试题推荐
TheUkrainenationallawmakershavedemanded______.[originaltext]National
Whatisthemainsubjectoftheconversation?[br][originaltext]M:I’mreally
Whatisthemainsubjectoftheconversation?[br][originaltext]M:I’mreally
Whatisthemainsubjectoftheconversation?[originaltext]M:I’mreallysorry,
Accordingtothenews,whereisthecenterofthequake?[br][originaltext]
WhatdoesthespeakersayabouttheroadbetweenMainandQuebec?[originaltext]
WhatdoestheUNreportfindabouttheChernobylnucleardisaster?[originaltext
WheredidCindygetherinformationabout"smart"cars?[br][originaltext]M:I
WheredidCindygetherinformationabout"smart"cars?[br][originaltext]M:I
WheredidCindygetherinformationabout"smart"cars?[originaltext]M:I’msor
随机试题
Thesunwarmstheearth,whichmakesitpossibleforplants(grow)______.togro
HowtoStudyEnglishinYourDream:theTheoryI.Introduction
全球投资业绩标准(GIPS)关于收益率的具体计算,以下描述错误的是()A.不同期
2017年7月29日,中国地质调查局组织实施的我国首次海域可燃冰试采圆满结束,此
阅读下面材料,回答问题。 一次,我正在布置作业:“每个生字写5遍。”就听有个同
醉酒的人犯罪()。A.应负刑事责任 B.不负刑事责任 C.造成严重后果的
(2015年真题)熊果酸的结构类型是( )。A.乌苏烷型 B.羊毛甾烷型
推荐反复性偏头痛者服用的是 (治疗头痛的处方药)A.布洛芬 B.谷维素 C
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
在建设工程施工过程的质量验收中,检验批的合格质量主要取决于( )。A.主控项目
最新回复
(
0
)