英语翻译（二）The central processing unit (CPU) is the heart of the

英语翻译
（二）The central processing unit (CPU) is the heart of the computer systems.Among other things,its configuration determines whether a computer is fast or slow in relation to other computers.The CPU is the most complex computer system component,responsible for directing most of the computer system activities based on the instructions provided.As one computer generation has evolved to the next,the physical size of the CPU has often become smaller and smaller,while its speed and capacity have increased tremendously.Indeed,these changes have resulted in microcomputers that are small enough to fit on your desk or your lap.
The CPU comprises the control unit and the arithmetic / logic unit (ALU).
The control unit is responsible for directing and coordinating most of the computer systems activities.It determines the movement of electronic signals between main memory and the arithmetic/logic unit,as well as the control signals between the CPU and input/output devices.
The ALU performs all the arithmetic and logical (comparison) functions — that is,it adds,subtracts,multiplies,divides,and does comparisons.These comparisons,which are basically “less than”,“greater than”,and “equal to”,can be combined into several common expressions,such as “greater than or equal to”.The objective of most instructions that use comparisons is to determine which instruction should be executed next.
（三）To open and transfer files,display text and image,you must use browser such as Microsoft’s Internet Explorer or Netscape’s Navigator.Browsers are programs that provide access to Web resources.For browsers to connect to other resources,the location or address must be specified.These addresses are called uniform resources locators (URL).Once the browser has connected to a Web site,a document file is sent to your computer.This document contains Hypertext Markup Language (HTML) commands.The browser interprets the HTML commands and displays the document as a web page.
Typically,the first page of a Web site is referred to as its home page.The home page presents information about the site along with references and hyperlinks,or connections to other documents that contain related information-text files,graphic images,audio,and video clips.These documents may be located on a nearby computer system or on one halfway around the world.The references appear as underlined and colored text and/or images on a Web page.To access the referenced material,all you do is click on the highlighted text or image.A link is automatically made to the computer containing the material,and the referenced material appears.

你这也太长了吧,低手帮不了,高手嫌它太简单不愿意帮啊!