单项选择题 The（）is a collection of modules serving as interface between hardware and software to provide a software platform.

单项选择题 The line of computing jobs waiting to be run on a computer system might be a （）.The jobs are serviced in the order of their arrival,that is ,the first in is the first out.

单项选择题 某主机的IP 地址为 10.100.100.01/20，其子网掩码是（）。