在Excel表处理中,假设单元格A1=1,A2=1.5,选择A1:A2单元格区域,并将鼠标指针指向该区域右下角的填充柄,拖动至A8单元格,则A8=______;之后,在单元格B1中输入公式“=SUM(A1:$A$8)”,则B1所显示的内容是______。______ is a device which enables digital microcomputers to communicate
across analog telephonelines.
A. The switch
B. The modem
C. The hub
D. The repeater