—Tom, the workers _____our new library already.  

—Really? I'll go there and borrow some books.    [ ]

A. decorated                

B. are decorating    

C. have decorated            

D. were decorated

多媒体计算机系统的两大组成部分是()。

A．多媒体器件和多媒体主机

B．音箱和声卡

C．多媒体输入设备和多媒体输出设备

D．多媒体计算机硬件系统和多媒体计算机软件系统