问题
单项选择题
Computer systems consist of two very different types of elements: Hardware, which includes all the physical things that can be touched and ______, which tells the hardware how to do.
A．Operating system
B．I/O devices
C．Courseware
D．Software
答案
参考答案：D
解析：题目的大意是：计算机系统由两种完全不同的部分组成：硬件(包含所有可以触摸到的物理部件)和软件(告诉硬件怎样做)。Operating system：操作系统，I/O devices：输入输出设备，Courseware：课件，Software：软件。