51● 在MPEG系列标准中， （63） 最适合在共用电话交换网（PSTN）上实时传输视频数据。
A.MPEG-1
B.MPEG-2
C.MPEG-4
D.MPEG-7
开始考试练习点击查看答案52● 要在网络上发布彩色动画文件，可以采用的存储格式是___(64)___。
A.BMP
B.JPEG
C.MP3
D.GIF
开始考试练习点击查看答案53● 为保证用户在网络上边下载边观看视频信息，需要采用___（65）__技术。
A.流媒体
B.数据库
C.数据采集
D.超链接
开始考试练习点击查看答案54● MIDI enables people to use （66） computers and electronic musical instruments. There are actually three components to MIDI, the communications " （67） ", the Hardware Interface and a distribution （68） called "Standard MIDI Files". In the context of the WWW, the most interesting component is the （69） Format. In principle, MIDI files contain sequences of MIDI Protocol messages. However, when MIDI Protocol （70） are stored in MIDI files, the events are also time-stamped for playback in the proper sequence. Music delivered by MIDI files is the most common use of MIDI today.
A.personal
B.electronic
C.multimedia
D.network
开始考试练习点击查看答案55● Certificates are （71） documents attesting to the （72） of a public key to an individual or other entity. They allow verification of the claim that a given public key does in fact belong to a given individual. Certificates help prevent someone from using a phony key to （73） someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a certificate also contains an （74） date, the name of the CA that issued the certificate, a serial number, and perhaps other information. Most importantly, it contains the digital （75） of the certificate issuer. The most widely accepted format for certificates is X.509 , thus, Certificates can be read or written by any application complying with X.509.
A.text
B.data
C.digital
D.structured
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