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
For more than thirty years scientists have been searching for signs of life on other planets. Most of these searches have been d
For more than thirty years scientists have been searching for signs of life on other planets. Most of these searches have been d
admin
2010-01-12
99
问题
For more than thirty years scientists have been searching for signs of life on other planets. Most of these searches have been done over the radio. The hope is that someone in outer space may be trying to get in touch with us. Scientists also have sent radio and television messages, as well as messages on spaceships traveling through space, on the chance that someone may be receptive to such messages.
Scientists are using powerful radio telescopes to "listen" to signals from about 1,000 stars, all within 100 light years of the earth. In addition, they will scan the entire sky to listen for radio messages from more distant stars. Using a computer, they will be able to monitor more than eight million channels at a time. Scientists are looking for any signal that stands out from the background noise.
Of the 200 billion stars in the Milky Way galaxy, scientists find that five percent of the stars are like our sun. Perhaps half of them have a planet like the earth. Such a planet would be a reasonable distance from the star for the temperatures to be right for the evolution of life. Believing that there are the inhabitable (that can be lived in) planets in our galaxy, most scientists agree that chances are that one or more of these planets support some life.
However, many scientists wonder whether intelligent life exists on other planets. Some believe that thirty years of searching without any intelligent messages show that no one is out there. They say that the evolution of intelligence comparable to ours is unlikely.
(44) Other scientists believe that our search hasn’t been long enough to rule out the possibility that intelligent life exists in our galaxy. Although our sun family is only about five billion years old, our galaxy is about 20 billion years old. In that time some scientists think it is likely that civilizations are much more advanced than ours. Perhaps these civilizations send us no signals; perhaps we have not recognized the signals they have sent us. If we hope to find intelligent life, these scientists believe that we have to keep looking.
The underlined phrase "on the chance" in the first paragraph means
选项
A、by chance
B、if possible
C、in the hope
D、for certain
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/7QJO777K
0
成人本科学位英语
相关试题推荐
I’mkeepingmy______open;Ihavenotmadeadecisiononthismatter.
Incountryaftercountry,talkofnonsmoker’srightisintheair.Whileamajorityofcountrieshavetakenlittle【C1】______noa
In1965,theUnitedStatesmadeimportantchangesinitsimmigrationlaws,allowingmanymoreimmigrantstocomeandentirelyel
Whatisaknowledgeworker?Knowledgeworkersarepeoplewhoroutinelyuseacomputerintheirworktoenhancetheirproductivit
BusinessinstitutionshavemoreprestigeinAmericansocietythananyotherkindoforganization,includingthegovernment.Most
Woman:Lotsofpeopleenjoydancing,doyou?Man:Believeitornot,that’sthelastthingI’deverwanttodo.Question:Whatd
Ateamcanaccomplishmuchmorethanthesumofitsindividualmembersandyetfrequentlygroupsofpeopleareseentoachievel
______scientistsdevelopnewwaysoffeedingthehumanrace,thecrowdedconditionsonearthwillmakeitnecessaryforustol
Everyyeartelevisionstationsreceivehundredsofcomplaintsabouttheloudnessofadvertisements.However,federalrulesforbi
Insomeways,theUnitedStateshasmadespectacularprogress.Firesnolongerdestroy18000buildingsastheydidintheGreat
随机试题
婴幼儿1~2岁时,可以进餐()次。
热效率是热力过程的经济性指标,是表示一个______关键性的指标。
对健康教育计划中总体目标组成的描述,错误的是
属于医疗保健机构提供婚前卫生指导的是属于医疗保健机构提供婚前卫生咨询的是
对侧肾功能良好的肾结石患者,下列哪种情况可作患侧肾切除
下图为住宅的公共楼梯平面图,下列选项()为错误选项。
—Willyoupleasesparemeafewminutestoacceptmyinterviewnow,Mr.YangLiwei?—____________.ButI’llbefreethisevening.
从所给的四个选项中,选项最合适的一个填入问号处,使之呈现一定的规律性:
面对不断出现的消费和产业成长热点,企业的注意力应首先放在寻求高成长产业的“先进入”_______上,以_______供不应求阶段的高额利润。而当进入者不断增加,竞争加剧后,企业则应将重点放在低成本为_______的价格竞争上,以保住和扩大市场份额。
Directions:Forthispart,youareallowed30minutestowriteanessaycommentingontheBeijinggovernment’sintroducingalot
最新回复
(
0
)