程序设计语言用于书写计算机程序，它包含语法、语义和(41)三个方面。程序设计语言通常都提供了三种控制结构，分别是顺序结构、(42)和循环结构。

(74)

The main feature of(72)is that they follow a first-come/first-served rule. For instance, the line of(73)waiting to be run on a computer system.

Whenever new information is entered, it must be stored somewhere in the computer's(70). RAM only(71)the data temporarily. That is, all information stored in the RAM will disappear if you switch the computer off.

(72)

(70)

A(68)is used to show you what the computer is doing. It is called(69)equipment as well as the keyboard, the mouse and the printer.

(68)

One solution to major security problems is(75), which are frequently installed to fix known security holes.

(66)is defined as the buying and selling of products and services over the Internet. It had included the handling of purchase(67)and funds transfers over computer networks from its inception.

(74)is a clickable string or graphic that points to another Web page or document.