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
Compact Disks If someone says to you your music CDs don’ t really hold any music on them, and they only have numbers recorde
Compact Disks If someone says to you your music CDs don’ t really hold any music on them, and they only have numbers recorde
admin
2014-08-13
65
问题
Compact Disks
If someone says to you your music CDs don’ t really hold any music on them, and they only have numbers recorded on them, you may not believe it. In fact, he is right in that sound is actually recorded onto the CDs as special numbers—a digital code. The code is pressed onto the CD as bumps(隆起)on a long spiral track almost five kilometers long. These bumps are an average of 0.5 microns(微米)wide.
A small laser beam shines onto the bumps as the CD turns. The light is reflected back to a receiver that records how the laser light bounces back. This lets the CD player turn the reflected light back into the original code. This means you can hear the original code as music.
Digital codes are used with many technologies. E-mail needs these kinds of code numbers. Space probes(探测仪)communicate with their ground station on earth using digital codes. Bar codes are read as digital codes in computer systems. Digital communications with cell phones need digital codes. Weather radios also tune in to specific signals using these codes.
There are many types of compact disks. One format is called CD-RWs. They can be recorded on and re-recorded on(rewritten on)as you would do with a floppy disk(软盘). Another format is the CD-ROM. The technology for recording on these disks is different from other CDs. These CDs have a dye layer that the CD writer can darken or leave clear. The clear and dark spots are the digital code. CD-ROM stands for Compact Disc—Read Only Memory. This disk is like a "super" floppy disk that can hold lots of information. One CD-ROM can hold the same amount of data as 500 floppy disks. Information is permanently recorded onto it. Computer games and other programs are considered to be CD-ROMs.
CDs were first sold to the public in 1982. These CDs still play well and sound fine. Current CDs are expected to last between 70 to 200 years. Of course, you can make sure your CDs last a long time by taking care of them.
Science keeps on developing. It may not be many more years before a completely new technology is invented and introduced to the public for music recording. In the meantime, there is no doubt you will continue to enjoy listening to your favorite music on CDs and play your favorite computer games on CD-ROMs.
One of the differences between CD-RWs and CD-ROMs is
选项
A、CD-ROMs can be used for a longer time
B、CD-ROMs cannot be rewritten on
C、CD-RWs hold more information
D、CD-RWs are merely used for music recording
答案
B
解析
根据第四段第三句可知,CD-RWs可以被重写。第四段第八句中的“CD—ROM stands forCompact Disk—Read Only Memory”则表明,CD—ROMs指的是“只读存储光盘”,即只能读取而不能重写的光盘。由此可知,两者的区别在于能否被重写。
转载请注明原文地址:https://kaotiyun.com/show/5TQd777K
本试题收录于:
职称英语理工类C级题库职称英语分类
0
职称英语理工类C级
职称英语
相关试题推荐
BreakingtheNewsaboutYourDiagnosis1.WhenIwasdiagnosedwithbreastcancernearlyayearago,Ifoundmyselfatalos
RiseinNumberofCancerSurvivorsCanceristhesecondleadingcauseofdeathintheUnitedStates,afterheartdisease.I
NewFoodsandtheNewWorldInthelast500years,nothingaboutpeople-nottheirclothes,ideas,orlanguages-haschangeda
Lookingtohelptheenvironment?Considerthefollowingsimpleideas.Turnoffelectricaldeviceswhenthey’renotbeinguse
MoviesMoviesarethemostpopularformofentertainmentformillionsofAmericans.Theygotothemoviestoescapetheirno
Sheperseveredinherideasdespiteobviousobjectionsraisedbyfriends.
EarBreakthroughNewresearchpublishedinthejournalCurrentBiologyhasaddedsignificantlytounderstandingofhowthee
Today,conventionalfinancialcontrolsarestillexercisedinsomeminorareassuchasbillingandvocationaltraining.Insome
PoolWatchSwimmerscandrowninbusyswimmingpoolswhenlifeguardsfailtonoticethattheyareintrouble.TheRoyalSoci
Inshort,Iamgoingtolivetheremyself.
随机试题
许多国家在制定政策过程中实行的听证制度的核心要求是()
若函数y=y(x)是由参数方程
如何理解社会主义初级阶段的按生产要素分配?
牛的胎盘类型属于
被甲类传染病病原体污染的污水、污物、粪便,有关单位必须按照以下规定进行处理()
下列关于工程项目绩效评价的说法,正确的有()。
按用人单位参保的建筑施工企业应以()为基数依法缴纳工伤保险费。
纤维增强塑料衬里施工时,其胶粘剂是()。
《党政机关公文处理工作条例》规定公文办理包括()。①公文签发;②发文办理;③收文办理;④整理归档。
Blackshavetraditionallybeenpoorlyeducated—lookatthecrisisinurbanpublicschools—anddeprivedofthesortsofoppor
最新回复
(
0
)