如果想给用户提供多余两个的选择，比如想把应用中的某个图片发给新浪微博或者facebook等平台应该使用什么控件？（）
A、模态
B、警告框
C、进度条
D、操作表
Which of the following would be an advantage to using a blade（刀片） server（服务器） as opposed to a rack（机架式） mount server？（）
A、 Blade servers allow for internal tape drives
B、 Blade servers offer more rack density
C、 Blade servers are typically faster
D、 Blade servers allow for more RAM
Where is the run date for an ‘at’ job located？（）
A、Within the job environment set up
B、Within the user data of the at job
C、In the file name preceeded with a userid
D、In a special file used by the cron daemon
A user is unable to determine the default system texteditor. How can the local administrator assist the user by identifying the default text editor for the system?（）
A、Login as the user and run 'echo $ENV'.
B、Login as root and run the 'env' command.
C、Login as root and 'cat /etc/environment'.
D、Login as the user and run the 'env' command.
Which command will enable the administrator to query the current network adapter configuration？（）
A、netstat -v
B、entstat -d
C、lsattr -El
D、lsdev -C -attr
交流供电系统由哪些部分组成？