面向对象方法学的出发点和基本原则是尽可能模拟人类习惯的思维方式，分析、设计和实现一个软件系统的方法和过程，尽可能接近于人类认识世界解决问题的方法和过程。因此面向对象方法有许多特征，如软件系统是由对象组成的；(50)；对象彼此之间仅能通过传递消息互相联系；层次结构的继承。

(68)

(66)

Viruses can't be transmitted by(74)and(75)is not a common route for virus infiltration.

(64)

Software refers to(70). The most important software on any computer is(71).

(62)

CPU doesn't mean(68). On a large computer system, a(69)links external devices to a channel.

Modern computers are electronic and(66)devices. The basic building block of a modem computer is a(67).

(60)

(59)