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
30
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://jikaoti.com/ti/cx6sFFFM
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
MenTooMaySufferFromDomesticViolenceNearlythreein10menhaveexperiencedviolenceatthehandsofanintimatepartn
EgyptFelledbyFamineEvenancientEgyptsmightypyramidbuilderswerepowerlessinthefaceofthefaminethathelpedbringdo
Intherecentpast,medicalresearchershaveshownthatheartdiseaseisassociatedwithcertainfactorsinourday-to-daylives
Intherecentpast,medicalresearchershaveshownthatheartdiseaseisassociatedwithcertainfactorsinourday-to-daylives
ProjectSkylabwasdesignedtodemonstratethatapersoncanworkandliveinspaceforprolongedperiodswithoutilleffects.
CosmeticsurgeryismorepopularintheUSthananywhereelse.Theeyeoperationwassuchafailurethatthewomanrefusedtop
PoolWatchSwimmerscandrowninbusyswimmingpoolswhenlifeguardsfailtonoticethattheyareintrouble.TheRoyalSo
SaunaCeremonialbathinghasexistedforthousandsofyearsandhasmanyforms,oneofwhichisthesauna.TheFinnshavepe
UnderstandingAutism1Autism(孤独症)isalife-longdevelopmentaldisabilitythatpreventsindividualsfromproperlyunderstanding
Sheshowslittleregardforthefeelingsofothersanddoesexactlywhatshewantsto.
随机试题
"Avoidtherush-hour"mustbethesloganoflargecitiesallovertheworld.Whereveryoulook,there’repeople,people,people.
()是指投资者按照企业章程,或合同、协议的约定实际投资。
A原始红细胞B原始粒细胞C原始单核细胞D原始淋巴细胞E早幼红细胞胞体直径10~18μm,圆形或椭圆形,胞核圆形或椭圆形,约占细胞直径的2/3以上,核染色质可浓集成粗密的小块,核仁模糊或消失,胞质量多,染不透明蓝或深蓝色,仍可见瘤状突起
妊娠末期的产科意外容易诱发DIC,主要是因
下列关于折现率说法正确的是()。
有限责任公司的设立条件包括()。
下列关于债券发行主体的说法中,正确的是()。
文本框Text1的KeyDown事件过程如下:PrivateSubText1_KeyDown(KeyCodeAsInteger,ShiftAsInteger) ...EndSub其中参数KeyCode的值表示的是发生此事件时(
Date:November2To:ElliotTurnbladFrom:SusanGerardSubject:InformationRequestHiElliot.Wejustreceivedaphonecall
Theoldladywasimmediatelysenttoanearbyhospitalwhenshe______fromheatstroke.
最新回复
(
0
)