回答{TSE}题： Computer Mouse The basic computer mouse is an amazingly clever invention with arelatively simple design that allows us to point at things on the computer andit is very productive. Think of all the things you can do with a mouse like selecting text for copying and pasting, drawing,and even scrolling on the page with the newer mice with the wheel. Most of ususe the computer mouse daily without stopping to think how it works until itgets dirty and we have to learn how to clean it. We learn to point at thingsbefore we learn to speak, so the mouse is a very natural pointing device. Othercomputer pointing devices include light pens, graphics tablets and touchscreens, but the mouse is still our workhorse. The computer mouse was invented in 1964 by Douglas Englehart ofStanford University. As computer screens became more popular and arrow keyswere used to move around a body of text, it became clear that a pointing devicethat allowed easier motion through the text and even selection of text would bevery useful. The introduction of the mouse, with the Apple Lisa computer in1983, really started the computer public on the road to relying on the mousefor routine computer tasks. How does the mouse work? We have to start at the bottom, so thinkupside down for now. It all starts with the mouse ball. As the mouse ball inthe bottom of the mouse rolls over the mouse pad, it presses against and turnstwo shafts. The shafts are connected to wheels with several small holes in them.The wheels have a pair of small electronic light-emitting devices calledlight-emitting diodes(LED) mounted on either side. One LED sends a light beamto the LED on the other side. As the wheels spin and a hole rotates by, thelight beam gets through to the LED on the other side. But a moment later thelight beam is blocked until the next hole is in place. The LED detects achanging pattern of light, converts the pattern into an electronic signal, andsends the signal to the computer through wires in a cable that goes out of themouse body. This cable is the tail that helps give the mouse its name. Thecomputer interprets the signal to tell it where to position the cursor on thecomputer screen. So far we have only discussed the basic computer mouse that mostof you probably have or bare used. One problem with this design is that themouse gets dirty as the ball rolls over the surface and picks up dirt.Eventually you have to clean your mouse. The newer optical mice avoid thisproblem by having no moving parts. {TS} Most computer users want to know how the computer mouse works.