首页
登录
职称英语
When we accept the evidence of our unaided eyes and describe the Sun as a y
When we accept the evidence of our unaided eyes and describe the Sun as a y
游客
2025-03-15
34
管理
问题
When we accept the evidence of our unaided eyes and describe the Sun as a yellow star, we have summed up the most important single fact about it--at this moment in time. It appears probable, however, that sunlight will be the color we know for only a negligibly (微不足道的) small part of the Sun’s history.
Stars, like individuals, age and change. As we look out into space, we see around us stars at all stages of evolution. There are faint blooded dwarfs so cool that their surface temperature is a mere 4,000 degrees Fahrenheit; there are scaring ghosts blazing at 100,000 degrees Fahrenheit and almost too hot to be seen, for the great part of their radia-tion is in the invisible ultraviolet range. Obviously, the "daylight" produced by any star depends on its temperature; today (and for ages to come) our Sun is at about 10,000 de-grees Fahrenheit, and this means that most of the Sun’s light is concentrated in the yellow band of the spectrum, falling slowly in intensity toward both the longer and shorter light waves.
That yellow "hump" will shift as the Sun evolves, and the light of the day will change accordingly.
It is natural to assume that as the Sun grows older, and uses up its hydrogen fuel-which it is now doing at the spanking rate of half a billion tons a sec-ond-it will become steadily colder and redder.
[br] What is the passage mainly about?
选项
A、Faint dwarf stars.
B、The evolution cycle of the Sun.
C、The Sun’s fuel problem.
D、The dangers of invisible radiation.
答案
B
解析
本题为主旨题。本文主要是谈太阳的演化周期,所以为B。对A项为微红的矮星、C项为太阳的燃料问题,都只是一带而过,不可作为本文的中心议题。本文没有谈及D项的不可见辐射的危险。
转载请注明原文地址:https://tihaiku.com/zcyy/3998026.html
相关试题推荐
WhenweaccepttheevidenceofourunaidedeyesanddescribetheSunasay
WhenweaccepttheevidenceofourunaidedeyesanddescribetheSunasay
WhenweaccepttheevidenceofourunaidedeyesanddescribetheSunasay
Ajudgemustbe______whenweighingevidence.A、interestedB、disinterestedC、sep
______Iacceptthatheisnotperfect,Idoactuallyliketheperson.A、WhileB、
______andhappy,Tonystoodupandacceptedtheprize.A、SurprisingB、Surprised
Ifhehadapplied(byAugust)15,theuniversity(hadaccepted)(him)(this)sem
Thereisagreatdealofevidence______thatmusicactivitiesengagedifferent
Auniversitygraduatedescribedasa"respectableandintelligent"womanis
Auniversitygraduatedescribedasa"respectableandintelligent"womanis
随机试题
Icouldjustseeabikeinthedistance,butIcouldn’t______whatcoloritwas.A
ItisveryimportantforstudentswhoarestudyingEnglishasasecondlan
E-mail1To:DBLOnlineFrom:MarshaSmithSubject:OrderDear
Upuntilthattime,hisinteresthadfocusedalmost______onfullymasteringth
一个圆上有5个不同的点,以这5个点中任意3个为顶点的三角形共有( )A.60个
债券评级的主要等级标准有()。 Ⅰ.A级债券 Ⅱ.B级债券 Ⅲ.C级
磁性药物微球中使其在体外磁场引导下,到达靶位的物质是A.铁磁性物质 B.单克隆
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
职业流行病学调查常用下列哪种方法?( )A.职业病体检 B.普查 C.典型
甲公司是一家电商平台,平台商家自行负责商品的采购、定价、发货以及售后服务,甲公司
最新回复
(
0
)