从网络高层协议的角度划分，网络攻击可以分为( )。

A．服务攻击与非服务攻击

B．主动攻击与被动攻击

C．木马攻击与主机攻击

D．嵌入式攻击与植入攻击

Computer hardware engineers research, design, develop, and test computer hardware and supervise its manufacture and (72) . Hardware refers to computer (73) , circuit boards, computer systems, and related equipment such as keyboards, modems, and printers.

A．chips

B．frame

C．structure

D．cell