外文原文:computerComputer is an electronic device that can receive a set of instructions or a program, and then by computing numerical data, or other forms of information processing to implement the program.If there is no development of computers, the modem high-tech world is not generated.In the whole society, different models and different sizes of computers are used to store and process various data, confidential documents from the government, banking transactions to private household accounts.The computer through the automation technology has opened up a new era in manufacturing, but they also enhance the performance of modern communication systems.In almost every field of research and application of technology, from building a model of the universe to produce tomorrows weather report, computer-free is not the necessary tools and their application in itself has opened up new areas of peoples speculation.Database services and computer network to make a variety of information sources available.The same advanced technology also made violation of personal privacy and commercial secrets possible.Computer crime has become an integral part of modern technology, the cost is one of the many risks.Outer HardwareLets start with the center of any computer system. Do you see something shaped like a box nearby? It will have a power switch and a light or two. It should also have a place or places to insert disks. This is the case that houses all of the important computer components. If it stands up tall, it is a tower case. If it sits flat, it is a desktop case. Ask your parents to let you look at the back of the computer (never do this without permission, because there is a lot of dangerous electricity back there!). You will see lots of cords and cables coming out of the back of the case and going to other computer parts like the monitor.Your computer case probably has a place to insert floppy disks or CDs. These are called the floppy disk drive and the CD-ROM. The floppy disk drive reads information from a very thin disk that is inside a flat, square plastic case. You can also write information to these disks and save it. CD-ROM is short for Compact Disk - Read Only Memory. A compact disk is a shiny, circular disk that stores information. A CD-ROM can only read information from the disk. Many new computers have a CD-RW (RW stands for ReWrite) instead of a CD-ROM. CD-RW allows you to write information to the disk as well as read from it. Also, some new computers have a DVD (Digital Video Disk) drive instead of a CD-ROM or CD-RW. A DVD looks just like a CD, but it holds much more information. You can watch movies, listen to music, or play computer games from DVDs. One important thing to know is that you can play CDs in a DVD player, but you cannot play DVDs in a CD player!Input Devices and Output DevicesThere are several ways to get new information or input into a computer. The two most common ways are the keyboard and the mouse. The keyboard has keys for characters (letters, numbers and punctuation marks) and special commands. Pressing the keys tells the computer what to do or what to write. The mouse has a special ball that allows you to roll it around on a pad or desk and move the cursor around on screen. By clicking on the buttons on the mouse, you give the computer directions on what to do. Other types of input devices allow you to put images into the computer. A scanner copies a picture or document into the computer. There are several types of scanners and some look very different, but most look like a flat tray with a glass pane and a lid to cover it. You can input photographs into a computer with a digital camera.The most common output device is a monitor. It looks a lot a like a TV and houses the computer screen. The monitor allows you to see what you and the computer are doing together. Speakers are output devices that allow you to hear sound from your computer.A printer is another common part of a computer system. It takes what you see on the computer screen and prints it on paper.Hardware on the InsideComputers are made of many electronic components or parts. These components each have a special job and they all work together to make your computer operate. Some components are hidden inside the computer, where you cant see them. Others can be seen partly from the outside.Power It Up!Every computer needs a power supply, to take electricity from your house and convert it into a current that works for your computer. When it is plugged into the wall, electricity travels from the electrical wires in your house into the computers power supply. When your computer is turned on, the power supply allows the converted electricity to travel to other components inside the computer.The motherboard gets its name because it is like a mother to all of the other circuit boards. Found at the bottom of a desktop case or the side of a tower case, the motherboard is the largest circuit board and h