概括大意与完成句子 [2018年职称英语考试卫生类概括句子与大意练习3]
Compact Disks
1 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.1 The code is pressed onto the CD as bumps on a long spiral track almost five kilometerslong.These bumps are an average of 0.5 microns wide.
2 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 player2 turn the reflected light back into the original code.This means you can hear the original code as music.
3 Digital codes are used with many technologies.E-mail needs these kinds of code numbers.Space probes 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.
4 There are many types of compact disk.One format is called CD-RWs.They can be recorded on and re-recorded on (rewritten on) as you would do with a floppy disk3.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.4 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.
5 CDs were first sold to the public in 1982.These CDs still play well and sound fine.Current CDs are expectedto last between 70 to 200 years.Of course, you can make sure your CDs last a long time by taking care of them.
6 Science keeps on developing.It may not be many more years before a completely new technology is invented5 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 CDs6 and playing your favorite computer games on CD-ROMs.
练习:
1.Paragraphs 1 & 2__________
2.Paragraph 3__________
3.Paragraph 4__________
4.Paragraph 5__________
A Digital Code Has Wide Applications
B Floppy Disks Are Outdated
C CDs Are Durable
D CD"s Working Principle Is Explained
E CD-RWs Play Better Than CD-ROWs
F CDs Are of Many Formats
5.One advantage of CD-RWs is that they can like floppy disks.
6.The author predicts it will not before a new technology is invented for music recording.
7.The laser beam-emitting device and the receiver are considered to of a CD player.
8.Space probes could not without using digital codes.
A shine on bumps
B take many more years
C be the key parts
D restore the original code
E be written on and rewritten on
F keep contact with their ground station efficiently
答案与题解：
1.D第一、二段介绍了 CD的工作原理。声音以数码的形式刻录到CD磁片上。要想听声音，就得用CD放机，CD机用激光照射CD，接收机接收和分析从 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，D是答案。
2.A 第三段第一句“ Digital codes are used with many technologies.”是主题句。本段其他句子提供例证，即应用领域。作者列举了 5个领域：电邮、航天通讯、条码、手机和天气预报。选项 A的“Digital code has wide applications”与主题句的意思完全吻合，所以是答案。
3.F 第四段第一句：“ There are many types of compact disks.”是主题句。本段其他句子列举了两种常用的CD格式(format)：一种是CD-RW，另一种是 CD-ROM。选项F的“CDs are of many formats”概括了本段的大意，是答案。
4.C 第五段说的是CD碟片经久耐用，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。
5.E 第四段中出现CD-RW这个词，介绍了“ They can be recorded on and re-recorded on (rewritten on)。这就是选E的依据。
6.B 第六段能找到与答案有关的句子，但 It may not be many more years before a completely new technology is invented and introduced to the public for music recording.
7.C 第二段说到在CD机上还原数码时依靠的是激光发射装置和按收器。由此我们可以推论出激光发射器和接收器是CD机的主要部件。所以C是答案。
8.F 第三段第三句“ Space probes communicate with their ground station on earth using digital codes.”是选F的依据。