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
The old belief that the universe never changes is quite wrong. Even before the invention of the telescope, astronomers noticed t
The old belief that the universe never changes is quite wrong. Even before the invention of the telescope, astronomers noticed t
admin
2019-06-10
33
问题
The old belief that the universe never changes is quite wrong. Even before the invention of the telescope, astronomers noticed that bright stars suddenly appear in the sky, and then later disappear.【R1】______In fact we now know that they are really old stars which are slowly dying. A recent case of a nova occurred in 1918, and one of the few people who saw this was the American astronomer Edward Barnard. He was driving along in a car, occasionally looking up into the sky. Suddenly he noticed a star that he had never seen before, and exclaimed, "That star should not be there!" He was in fact watching the explosion of a nova.
【R2】______As they do so, they let out huge clouds of material. Sometimes as large as the earth, and these explode into space at a speed of about 8, 000, 000 kilometers per hour. When this happens, the hotter parts of the star become visible, and this is why novae are so bright. Although the explosions are huge on a human scale, they only consume a small part of the dying star’s energy.
【R3】______Indeed, there are even some stars which explode once a fortnight.
There are other old stars which do not die slowly, but are completely destroyed by one great explosion.【R4】______The explosion of a supernova is equivalent to about a million, million, million, million hydrogen bombs going off at the same time. Just before the explosion the star’s density become very great and it spins at a very high speed. A matchbox of material taken from the star at that time would weigh about 1,000 tons, and the star would be turning at about 16,000,000 kilometers per hour.【R5】______One supernova which Chinese astronomers observed in 1054 can still be seen by us today. It has been shining for at least nine hundred years.
A. Novae are old stars which are slowly dying.
B. They are known as " supernovae."
C. The death is a slow one, and the star may continue to explode for thousands of years.
D. The explosion of a supernova is like a cosmic bomb.
E. The explosion itself occurs suddenly, in the space of a minute, but the supernova continues to shine long after the event.
F. These stars were called "novae" because they were thought to be new.
【R5】
选项
答案
E
解析
文章的第三段从多个维度描述了超新星的爆炸:释放的能量、速度和时间。空格后面为举例说明超新星爆炸后仍可以长时间发光。因此,选项E为最佳答案。
转载请注明原文地址:https://jikaoti.com/ti/g3NYFFFM
0
考博英语
相关试题推荐
Cellscannotremainaliveoutsidecertainlimitsoftemperature,andmuchnarrowerlimitsmarkthebound-ariesofeffectivefunc
Cellscannotremainaliveoutsidecertainlimitsoftemperature,andmuchnarrowerlimitsmarkthebound-ariesofeffectivefunc
Thecompanywasfinancially______andalmostwenttobankruptcyduringlastyear’seconomicrecession.
Asweknow,bloodtypesAandBcannotreceiveAB,butABmayreceiveAorB.TypeOcangivetoanyothergroup;henceitisoft
PitythosewhoaspiretoputtheinitialsPhDaftertheirnames.After16yearsofcloselysupervisededucation,prospectivedoc
TheEconomistIntelligenceUnit(EIU)earnestlyattemptstomeasurewhichcountrywillprovidethebestopportunitiesforahealth
Iamwritingthisathomebecauselastweekmyergonomic(符合人体工程学的)chairattheofficefellapart,unableanylongertobearmyw
Scienceisanenterpriseconcernedwithgaininginformationaboutcausality,ortherelationshipbetweencauseandeffect.Asim
Thereisnodenyingthatstudentsshouldlearnsomethingabouthowcomputerswork,justasweexpectthematleasttounderstand
Ironically,theintellectualtoolscurrentlybeingusedbythepoliticalrighttosuchharmfuleffectoriginatedontheacademic
随机试题
管理经济学研究的对象是()
“寒热并用”的方剂是( )
闭合性肋骨骨折患者,出现下列哪项征象提示合并肺或支气管损伤
男性,68岁,行走时突然跌倒,不省人事,呼之不应,呼吸停止,颈动脉搏动消失,心音消失。诊断是
维持蛋白质空间构象的作用力不包括
现汇是指可自由兑换的汇票。()
简述会计基本假设。
材料:在学习“生物的性状”这一内容时,教师设计了以下4个教学活动。活动1:教师通过多媒体课件展示一些明星及其家人的照片,让学生将可能与明星具有血缘关系的人找出来并说明原因。学生说出的原因可能围绕有血缘关系的人在外形上的一些相同特点进行展
A.成釉器B.牙乳头C.牙囊D.缩余釉上皮E.Malassez上皮剩余形成牙髓组织的是()。
求f(x,y)=x+xy一x2一y2在闭区域D={(x,y)|0≤x≤1,0≤y≤2}上的最大值和最小值.
最新回复
(
0
)