Generally, a computer is any device that can perform. numerical calculations. Currently, 【1】, the term usually refers【2】an electronic device that can【3】a series of tasks according to a set of instructions.

In 1953 there were only about 100 computers【4】use in the world. Today hundreds of millions of computers are【5】in homes, schools, businesses, government offices, and universities for almost every conceivable【6】.

Modern desktop【7】computers, or PCs, are many times more powerful than the huge, million dollar【8】of computers of the 1960s and 1970s. Most PCs can perform. from 400 million to several billion operations per second. These computers are used not【9】for household management and personal entertainment, but also for most or the automated【10】required by small business. The fastest desktop computers are called workstations, and they are generally used for scientific, engineering, or advanced business application.

(1)

A computer is a machine designed to perform. work mathematically and to store and select information that has been fed into it. It is nm by either mechanical or electronic means. These machines can do a great deal of complicated work in a very short time. A large computer, for example, can add or subtract nine thousand times a second, multiply a thousand times a second, or divide five hundred times a second. Its percentage of error is about one in a billion digits. It has been estimated that human beings making calculations average about one mistake per two hundred digits.

The heart of an electronic computer lies in its vacuum tubes, or transistors. Its electronic circuits work a thousand times faster than the nerve cells in the human brain. A problem that might take a human being two years to solve can be solved by a computer in one minute, but in order to work properly, a computer must be given instructions--it must be programmed. Computers can be designed for many specialized purposes--they can be used to prepare payrolls, guide airplane flights, direct traffic, even to play chess. Computers play an essential role in modern automation in many plants and factories throughout the world.

A computer is a machine designed to ______.

A．perform. work mathematically

B．perform. complicated calculations

C．store and select information

D．a(chǎn)ll of the above

聽(tīng)力原文： A computer is a machine designed to perform. work mathematically and to store and select information that has been fed into it. It is run by either mechanical or electronic means. These machines can do a great deal of complicated work in a very short time. A large computer, for example, can add or subtract nine thousand times a second, multiply a thousand times a second, or divide five hundred times a second. Its percentage of error is about one in a billion digits. It has been estimated that human beings making calculations average about one mistake per two hundred digits.

The heart of an electronic computer lies in its vacuum tubes, or transistors. Its electronic circuits work a thousand times faster than the nerve cells in the human brain. A problem that might take a human being two years to solve can be solved by a computer in one minute, but in order to work properly, a computer must be given instructions--it must be programmed.

Computers can be designed for many specialized purposes--they can be used to prepare payrolls, guide airplane flights, direct traffic, even to play chess. Computers play an essential role in modern automation in many plants and factories throughout the world.

(33)

A．One in a billion digits.

B．Zero.

C．One mistake per two hundred digits.

D．One in a million digits.

Computer and Its Kind

??

計(jì)算機(jī)及其種類(lèi)

??A computer is an electronic device that can receive a set of instructions, or program, and then carry out this program by performing calculations on numerical data or by compiling and correlating other forms of information.

??The modern world of high technology could not have come about except for the development of the computer. Different types and sizes of computers find uses throughout society in the storage and handling of data, from secret governmental files to banking transactions to private household accounts^[1]. Computers have opened up a new era in manufacturing through the techniques of automation, and they have enhanced modern communication systems. They are essential tools in almost every field of research and applied technology, from constructing models of the universe to producing tomorrow's weather reports, and their use has in itself opened up new areas of conjecture. Database services and computer networks make available a great variety of information sources^[2]. The same advanced techniques also make the invasions of privacy and restricted information sources possible, and computer crime has become one of the many risks that society must face if it is to enjoy the benefits of modern technology.

??

Types of Computers

??1. Microcomputer

??A microcomputer is a desktop or notebook size computing device that uses a microprocessor as its Central Processing Unit, or CPU. Microcomputers are also called Personal Computers (PCs) , home computers, small business computers, and micros. The smallest, most compact are called laptops. When they first appeared, they were considered single user devices, and they were capable of handling only 4, 8, or 16 bits of information at one time. More recently the distinction between microcomputers and large, mainframe computers as well as the smaller mainframe type systems called minicomputers has become blurred, as newer microcomputer models have increased the speed and data handling capabilities of their CPUs into the 256 bit, or even much more bit multiuser range.

??Microcomputers are designed for use in homes, schools, and office settings. Within the home, they can serve both as a tool for home management balancing the family checkbook, structuring the family budget, indexing recipes and as a recreational device playing computer games, cataloging records and books. School children can use microcomputers for doing their homework, and in fact many public schools now employ the devices for programmed learning and computer literacy^[3]courses. Small businesses may purchase microcomputers for word processing, bookkeeping, the storage and handling of mailing lists and so on.

??Desktop Computer

??A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Prior to the wide spread of microprocessors a computer that could fit on a desk was considered remarkably small. Today the phrase usually indicates a particular style of computer case. Desktop computers come in a variety of styles ranging from large vertical tower cases to small form factor models that can be tucked behind an LCD^[4]monitor. In this sense the term "desktop" refers specifically to a horizontally-oriented case, usually intended to have the display screen placed on top to save space on the desk top. Most modern desktop computers have separate screens and keyboards. A specialized form of desktop case is used for home theater PC systems, incorporating front-panel mounted controls for audio and video.

??Personal Digital Assistant (PDA)^[5]

??A personal digital assistant (PDA) is a handheld computer, also known as a palmtop computer. Newer PDAs also have both color screens and audio capabilities, enabling them to be used as mobile phones, smartphones, web browsers, or portable media players. Many PDAs can access the Internet, intranets or extranets via Wi-Fi^[6], or Wireless Wide-Area Networks (WWANs^[7]). Many PDAs employ touch screen technology.

??Tabjet^[8]PC

??A Tablet PC is a laptop mobile computer, equipped with a touchscreen or graphics tablet/screen hybrid technology which allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse. This form factor offers a more mobile way to interact with a computer. Tablet PCs are often used where normal notebooks are impractical or unwieldy, or do not provide the needed functionality.

??Laptop^[9]

??A laptop (also known as a notebook) is a personal computer designed for mobile use small enough to sit on one's lap. A laptop includes most of the typical components of a typical desktop computer, including a display, a keyboard, a pointing device, a touchpad, also known as a trackpad, or a pointing stick, as well as a battery, into a single small and light unit. The rechargeable battery required is charged from an AC/DC adapter and typically stores enough energy to run the laptop for several hours.

??2. Minicomputer

??A minicomputer is a mid-level computer built to perform complex computations while dealing efficiently with a high level of input and output from users connected via terminals. Minicomputers also frequently connect to other minicomputers on a network and distribute processing among all the attached machines. Minicomputers are used heavily in transaction processing applications and as interfaces between mainframe computer systems and wide area networks.

??3. Mainframe Computer

??A mainframe computer is a high level computer designed for the most intensive computational tasks. Mainframe computers are often shared by multiple users connected to the computer via terminals. The most powerful mainframes, called supercomputers, perform highly complex and time-consuming computations and are used heavily in both pure and applied research by scientists, large businesses, and the military.

??4. Others

??·Servers

??A server usually refers to a computer that is dedicated to providing a service. For example, a computer dedicated to a database may be called a "database server". "File servers" manage a large collection of computer files. "Web servers" process web pages and web applications. Many smaller servers are actually personal computers that have been dedicated to providing services for other computers.

??A server is a computer program that provides services to other computer programs and their users in the same or other computer. The physical computer that runs a server program is also often referred to as server.

??Services can be supplied centrally by the use of a server; in other cases all the machines on a network have the same status with no dedicated server, and services are supplied peer-to-peer^[10].

??·Workstation

??Workstations are computers that are intended to serve one user and may contain special hardware enhancements not found on a personal computer.

??It is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems. The term workstation has also been used to refer to a mainframe computer terminal or a PC connected up to a network.

??Historically, workstations had offered higher performance than personal computers, especially with respect to graphics and CPU power, memory capacity and multitasking ability. They are optimized for display and manipulation of different types of complex data such as?3D mechanical design,?engineering simulation (e. g. computational fluid dynamics), animation and rendering of images, and mathematical plots. Consoles consist of a high resolution display, a keyboard and a mouse at a minimum, but also offer multiple displays, graphics tablets, SpaceBalls, etc. Workstations are the first segment of the computer market to present advanced accessories and collaboration tools.

??·Embedded computers

??Embedded computers are computers that are a part of a machine or device. Embedded computers generally execute a program that is stored in non-volatile memory and is only intended to operate a specific machine or device. Embedded computers are very common. Embedded computers are typically required to operate continuously without being reset or rebooted, and once employed in their task the software usually cannot be modified. An automobile may contain a number of embedded computers; however, a washing machine and a DVD player would contain only one. The central processing units (CPUs) used in embedded computers are often sufficient only for the computational requirements of the specific application and may be slower and less expensive than CPUs found in personal computers.

??·Supercomputer

??In computer science, supercomputers are large, extremely fast, and expensive computers used for complex or sophisticated calculations, typically, machines capable of pipelining instruction execution and providing vector instructions. A supercomputer can, for example, perform the enormous number of calculations required to draw and animate a moving spaceship in a motion picture^[11]. Supercomputers are also used for weather forecasting, large scale scientific modeling, oil exploration and so on and so like.

??

Future Developments

??One ongoing trend in computer development is microminiaturization, the effort to compress more circuit elements into smaller and smaller chip space. Researchers are also trying to speed up circuitry functions through the use of superconductivity, the phenomenon of decreased electrical resistance observed as objects exposed to very low temperatures become increasingly colder^[12]. The fifth-generation computer, the effort to develop computers that can solve complex problems in what might eventually be called creative ways, is another trend in computer development, the ideal goal being true artificial intelligence^[13].

??Quantum Computer

??A quantum computer^[14], quite different from classical current computers, is a device that harnesses physical phenomenon unique to quantum mechanics to realize a fundamentally new mode of information processing. In a quantum computer, the fundamental unit of information called a quantum bit (or qubit), is not binary but rather more quaternary in nature.?A qubit can exist not only in a state corresponding to the logical state 0 or 1 as in a classical bit, but also in states corresponding to a blend or superposition of these classical states. In other words, a qubit can exist as a 0, a 1, or simultaneously as both 0 and 1, with a numerical coefficient representing the probability for each state.

??DNA Computer

??DNA computing^[15]is a form of computing which uses DNA, biochemistry and molecular biology, instead of the traditional silicon-based computer technologies. DNA computing, or. more generally, molecular computing, is a fast developing interdisciplinary area and is fundamentally similar to parallel computing in that it takes advantage of the many different molecules of DNA to try many different possibilities at once. And DNA computers are faster and smaller than any other computer built so far.

??Optical Computer^[16]

??An optical computer is a computer that uses light instead of electricity (i. e.photonsrather thanelectrons) to manipulate, store and transmit data. Optical computer technology is still in the early stages: functional optical computers have been built in the laboratory, but none have progressed past the prototype stage.

??Molecule Computer

??A molecular computer that uses enzymes to perform calculations has been built and it is believed enzyme-powered computers could eventually be implanted into the human body and used to, for example, tailor the release of drugs to a specific person's metabolism.

??It used two enzymes to trigger two interconnected chemical reactions. Two chemical components-hydrogen peroxide^[17]and glucose^[18]-were used to represent input values A and B. The presence of each chemical corresponded to a binary 1, while the absence represented a binary 0. The chemical result of the enzyme-powered reaction was determined optically.

??Notes

??[1]... from secret governmental files to banking transactions to private household accounts.

??①from... to:從……到。

??②banking transactions to：對(duì)……的金融交易此處指銀行轉(zhuǎn)賬，大意為：從政府的秘密文件到銀行對(duì)私人家庭賬戶(hù)的賬目往來(lái)。

??[2]... make available a great variety of information sources. 本句和下一句均為倒裝句，在賓語(yǔ)過(guò)長(zhǎng)而其補(bǔ)語(yǔ)太短的情況下，常使用這一結(jié)構(gòu)。原結(jié)構(gòu)應(yīng)為“to make sth. available/possible”。

??[3]computer literacy計(jì)算機(jī)掃盲?！發(fā)iteracy”，原意為“識(shí)字，掃盲，有讀和寫(xiě)的能力”，這里引申為“使用計(jì)算機(jī)的基本能力”。

??[4]LCD (liquid crystal display)液晶顯示，通過(guò)將具有極性分子結(jié)構(gòu)的液體混合物夾在兩個(gè)透明的電極間構(gòu)成的顯示方式。

??[5]Personal Digital Assistant (PDA)個(gè)人數(shù)字助理。它是一種輕便的掌上型計(jì)算機(jī)，既有通信功能，又有個(gè)人組織功能，包括日歷、筆記、數(shù)據(jù)庫(kù)、計(jì)算器等。

??[6]Wi-Fi (Wireless Fidelity)無(wú)線(xiàn)保真，是一種可以將個(gè)人電腦、手持設(shè)備，如PDA、手機(jī)等終端以無(wú)線(xiàn)方式互相連接的技術(shù)。Wi-Fi一詞由Wi-Fi產(chǎn)業(yè)聯(lián)盟(Wi-Fi Alliance)提出。

??[7] WWAN (Wireless Wide-Area Networks)無(wú)線(xiàn)廣域網(wǎng)，WWAN技術(shù)是使得筆記本電腦或者其他的設(shè)備裝置在蜂窩網(wǎng)絡(luò)覆蓋范圍內(nèi)可以在任何地方連接到互聯(lián)網(wǎng)，其下載速度可以與DSL相媲美。

??[8]tablet圖形輸入板，在工程、設(shè)計(jì)和解釋類(lèi)的應(yīng)用程序中用于輸入圖形位置信息的設(shè)備。

??[9]laptop便攜式計(jì)算機(jī)，一種為便于旅行時(shí)使用而設(shè)計(jì)的小型手提式計(jì)算機(jī)，可用電池或交流電源供電。

??[10]peer-to-peer (P2P.)點(diǎn)對(duì)點(diǎn)技術(shù)，又稱(chēng)對(duì)等互聯(lián)網(wǎng)絡(luò)技術(shù)，是一種網(wǎng)絡(luò)新技術(shù)，依賴(lài)網(wǎng)絡(luò)中參與者的計(jì)算能力和帶寬，而不是把依賴(lài)都聚集在較少的幾臺(tái)服務(wù)器上。P2P網(wǎng)絡(luò)通常用于通過(guò)Ad Hoc連接來(lái)連接節(jié)點(diǎn)，也被使用在類(lèi)似VoIP等實(shí)時(shí)媒體業(yè)務(wù)的數(shù)據(jù)通信中。純點(diǎn)對(duì)點(diǎn)網(wǎng)絡(luò)沒(méi)有客戶(hù)端或服務(wù)器的概念，只有平等的同級(jí)節(jié)點(diǎn)，同時(shí)對(duì)網(wǎng)絡(luò)上的其他節(jié)點(diǎn)充當(dāng)客戶(hù)端和服務(wù)器。也有些專(zhuān)家稱(chēng)P2P是點(diǎn)對(duì)點(diǎn)技術(shù)，但其實(shí)是錯(cuò)的，實(shí)應(yīng)解作群對(duì)群(Peer-to-Peer)。在虛擬私人網(wǎng)絡(luò)VPN(Virtual Private Network)中，也有P2P這個(gè)名稱(chēng)，它才應(yīng)解作點(diǎn)對(duì)點(diǎn)(Point-to-Point)。

??[11]motion picture電影。

??[12]..., the phenomenon of decreased electrical resistance observed as objects exposed to very low temperatures become increasingly colder. 此處，過(guò)去分詞“observed”用作定語(yǔ)，修飾名詞“the phenomenon”，它所帶的狀語(yǔ)從句中的過(guò)去分詞短語(yǔ)“exposed to”修飾名詞“objects”。可以翻譯成“當(dāng)暴露于超低溫的物體的溫度越來(lái)越低時(shí)，即可觀察到電阻值降低的現(xiàn)象”。

??[13]...，the ideal goal being true artificial intelligence. 分詞獨(dú)立結(jié)構(gòu)，句中起說(shuō)明作用，可翻譯成“理想的目標(biāo)是真正的人工智能”。

??[14]quantum computer量子計(jì)算機(jī)，由理查德·費(fèi)曼提出，是從物理現(xiàn)象的模擬而來(lái)的。量子電腦能做出對(duì)數(shù)運(yùn)算，而且速度遠(yuǎn)勝傳統(tǒng)電腦。這是因?yàn)榱孔硬幌癜雽?dǎo)體只能記錄0與1，可以同時(shí)表示多種狀態(tài)，一個(gè)40位元的量子電腦，就能解開(kāi)1024位元電腦花上數(shù)十年解決的問(wèn)題。

??[15]DNA computing，DNA運(yùn)算，或譯DNA計(jì)算，是一種電腦運(yùn)算形式，利用DNA、生物化學(xué)以及分子生物學(xué)原理，而非傳統(tǒng)上以硅為基礎(chǔ)的電腦技術(shù)。

??[16]optical computer光學(xué)計(jì)算機(jī)，利用可見(jiàn)光或紅外光而不是電流進(jìn)行數(shù)據(jù)處理，從全息存儲(chǔ)、激光存儲(chǔ)或存儲(chǔ)庫(kù)輸入數(shù)據(jù)的計(jì)算器，多用于指紋鑒定和圖像清晰化的處理過(guò)程。

??[17]hydrogen peroxide過(guò)氧化氫：一種無(wú)色、重、具有很強(qiáng)氧化作用的液體H₂O₂。

??[18]glucose葡萄糖：一種單糖，C₆H₁₂O₆，廣見(jiàn)于大多數(shù)動(dòng)植物組織。

You can conclude that the author thinks that if a person took a computer course, that person would learn ______.

A．very quickly

B．a(chǎn)s much as the author's co-workers

C．to think like a computer

D．a(chǎn)bout computers the easy way

Can a computer think? That depends on what you mean by "think". If solving a mathematical problem is "thinking", then a computer can "think" and do so much faster than a man. Most mathematical problems can be solved quite mechanically by repeating certain straightforward processes over and over again. Even the simple computers of today can be geared for that.

It is frequently said that computers solve problems only because they are "programmed" to do so. They can only do what men have them do. One must remember that human beings also can only do what they are "programmed" to do. Our genes "program" us.

Our "program" is so much more enormously complex, though, that we might like to define "thinking" in terms of the creativity that goes into writing a great play or composing a great symphony, into developing a brilliant scientific theory or a profound moral judgment. In that sense, computers certainly can't think and neither can most humans.

Surely, though, if a computer can be made complex enough, it can be as creative as we. If it could be made as complete as a human brain, it could be the equivalent of a human brain and do whatever a human brain can do.

But how lung will it take to build a computer complex enough to duplicate(復(fù)制) the human brain? Perhaps not as long as some think. Long before we approach a computer as complex as our brain, we will perhaps build a computer that is at least complex enough to design another computer more complex than itself. This more complex computer could design one still more complex and so on.

In other words, once we pass a certain critical point, the computers take over and there is a "complexity explosion". In a very short time thereafter, computers may exist that not only duplicate the human brain but far go beyond it.

What information about computers can we get from the passage?

A．They are simple and they operate mechanically.

B．They can solve all kinds of difficult problems.

C．Computers are so advanced that they will control human being someday in the future.

D．They are not as complicated as human brain.