在选择多媒体数据压缩算法时需要综合考虑 （ ） 。
A、数据质量和存储要求 
B、数据的用途和计算要求 
C、数据质量、数据量和计算的复杂度 
D、数据的质量和计算要求 

在MPEG系列标准中， （ ） 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

要在网络上发布彩色动画文件，可以采用的存储格式是（ ）。
A、BMP
B、JPEG
C、MP3
D、GIF

MIDI enables people to use （1） computers and electronic musical instruments. There are actually three components to MIDI, the communications " （2） ", the Hardware Interface and a distribution （3） called "Standard MIDI Files". In the context of the WWW, the most interesting component is the （4） Format. In principle, MIDI files contain sequences of MIDI Protocol messages. However, when MIDI Protocol （5） 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.
（1）A、personal 
B、electronic 
C、multimedia 
D、network
（2）A、device 
B、protocol 
C、network 
D、controller
（3） A、format 
B、text 
C、wave 
D、center
（4）A、Video 
B、Faxmail 
C、Graphic 
D、Audio
（5） A、messages 
B、packets 
C、frame 
D、information 

 Certificates are （1） documents attesting to the （2） 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 （3） someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a certificate also contains an （4） date, the name of the CA that issued the certificate, a serial number, and perhaps other information. Most importantly, it contains the digital （5） 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.
（1） A、text 
B、data 
C、digital 
D、structured
（2）A、connecting 
B、binding 
C、composing 
D、conducting
（3） A、impersonate 
B、personate 
C、damage 
D、control
（4）A、communication 
B、computation 
C、expectation 
D、expiration
（5）A、signature 
B、mark 
C、stamp 
D、hypertext