题目详解：
Compact Disks，就是我们很熟悉的CD的全称，其中compact原意是装填紧密的;disk, 也可以写成disc, 意思是扁平的圆盘状物、磁盘。Compact disk就是激光唱片，或光盘。
接下来，先解前半部分题目，即概括段落大意，我们需要概括1，2，3，4，5段。在阅读如上段落之前先了解被选答案的大意。
ADigital(数字的) code(代码) has wide(广泛的) applications(应用).
BFloppy(松软的) disks are outdated(过时的).
CCDs are durable(经久耐用的).
DCD's working principle(工作原理) is explained(被解释).
ECD-RWs(一种光盘的种类) play(播放) better than CD-ROMs.
FCDs are of(具有) many formats(格式).
阅读一、二段：
1 If someone(有人) says to you(对你说) your music CDs don't really hold(包含、有) any music on them, and they only have numbers(数字) recorded(被刻录下来) on them, you may not believe(相信) it. In fact(事实上), he is right(正确的) in that (复合介词，表示原因，相当于because)sound(声音) is actually(实际上) recorded onto the CDs as(介词，作为) special (特殊的)numbers - a digital code(数码). The code is pressed(挤、压) onto the CD as(像，同义词like) bumps (凸起部分)on a long (长长的)spiral(螺旋形的) track (轨迹、轨道)almost five kilometers(5公里) long. These bumps are an average(平均的) of 0.5 microns(微米) wide(宽)
2 A small laser(激光) beam (光束)shines (照射)onto the bumps as (当)the CD turns(旋转). The light is reflected(被反射) back to a receiver(接受器) that(引导定语从句) records(记录) how the laser light (激光)bounces(弹起) back. This lets the CD player(CD播放机) turn the reflected(被反射的) light back into the original(最初的、原先的) code. This means(意味着) you can hear the original code as music.
分析：经过我们逐字逐句的阅读，可以看出第一、二段主要就是讲CD的工作原理。描述得很详细：声音以数码的形式被刻录到CD碟片上。要回听声音，就得用 CD 放音机，CD 机用激光照射 CD，接收器收和分析从 CD 反射回来的激光波，还原为原来的数码，再转换为原来的声音。所以，我们应该选择D。
阅读第三段：
Digital codes are used(被用于) with many technologies(技术). E-mail needs(需要) these kinds(种类) of code(代码) numbers. Space(太空、空间) probes(探测器，同义词explorer) communicate (沟通、联络)with their ground station(地面站) on earth using digital codes. Bar codes(条形码) are read as digital codes in computer systems(在计算机系统中). Digital communications(数码通讯) with(使用) cell phones (手机)need digital codes. Weather(天气) radios(无线电) also tune into(转变成) specific(具体的)signals(信号)using these codes.
分析：实际上，本段第一句就是中心：Digital codes are used with many technologies.后面的内容是作者例举了在5个领域中数码的具体应用：电邮、航天通讯、条码、手机和天气预报。所以这题选择A，它的表述与主题句的意思完全吻合
阅读第四段：
There are many types(种类，同义词kinds) of compact disks. One format(格式) is called CD-RWs. They can be recorded on and re-recorded(反复被刻录) on (rewritten on) as(正如) you would do with a floppy disk(软盘)(这句话说明CD-RW的工作原理和软盘一样。). Another format is the CD-ROM. The technology for recording on these disks is different from other CDs(整句的意思是：用这种光盘存储数据的技术跟其它的光盘不同。). These CDs have a dye layer(染色层) that(定语从句) the CD writer(光盘刻录机) can darken(涂黑) or leave (留出)clear(空白). The clear and dark spots(点) are the digital code. CD-ROM stands for(代表) Compact Disc - Read Only Memory(是读存储光盘的简称). This disk is like(像) a "super"(超级的) floppy disk that can hold(包括、包含) lots of information. One CD-ROM can hold the same amount of data as (和the same构成固定搭配，意思和。。。一样)500 floppy disks(句子意思：一张CD-ROM可以包括相当于500张软盘所存储的数据). Information is permanently(永久地) recorded onto it. Computer games and other programs(程序) are considered(被看作) to be CD-ROMs.
分析：别看这段长，事实上大意很容易掌握，开头第一句就是中心句：There are many types of compact disks。后面就是例举了两种常用的 CD 格式 (format), 一种是 CD-RW，另一种是 CD-ROM.所以，选择答案F。
阅读第五段：
CDs were first(首先) sold(被出售) to the public(公众) in 1982. These CDs still play(播放) well and sound(听起来) fine. Current (现在、目前)CDs are expected(被期望) to last(延续) between 70 to 200 years. Of course, you can make sure (确定)your CDs last a long time by(通过，表示方式) taking care of them.
分析：该段比较简单，用数字作为对观点的阐述，大意是：1982年上市的 CD 碟片至今还能使用，其音质依旧。现在上市的 CD，更加耐用，如果使用得当，其寿命可达70-200年。选项 C 用了durable 予以概括是很恰当的，所以，C是答案。
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