问题
单项选择题
(74) systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and (75) on the disk, and controlling peripheral devices such as disk drives and printers.
A．contents
B．diectories
C．directions
D．direct
答案
参考答案：B
解析：试题74-75
[分析]：
操作系统执行一些基本的任务，例如：识别键盘上的输入，把输出发送到显示屏上，保持磁盘上文件与目录的跟踪，并且控制诸如磁盘驱动器与打印机之类的外部设备。