开班系统启动后，POS程序会自动运行，启动成功后会在POS上显示“登录”按钮，点击后系统进入（）登录页。

A、加油机授权

B、油站出勤与收银机

C、密码进入界面

D、新建

MIDI enables people to use (51) computers and electronic musical instruments. There are actually three components to MIDI, the communications " (52) ", the Hardware Interface and a distribution (53) called "Standard MIDI Files". In the context of the WWW, the most interesting component is the (54) Format. In principle, MIDI files contain sequences of MIDI Protocol messages. However, when MIDI Protocol (55) 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.

（51）是（）

A.personal

B.electronic

C.multimedia

D.network