数据库管理系统(DBMS)是(20)的核心软件。DBMS提供的数据操作语言(DML)可以实现的操作有(21)。使用DBMS管理数据的特点有(22)：

①数据结构化；

②数据独立性；

③数据安全性；

④数据完整性；

⑤并发控制；

⑥故障恢复。

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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.