The basic computer mouse is an amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive. Think of all the things you can do with a mouse like selecting text for copying and pasting1，drawing，and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think2 how it works until it gets dirty and we have to learn how to clean it. We learn to point at things before we learn to speak，so the mouse is a very natural pointing device. Qther computer pointing devices include light pens，graphics tablets and touch screens，but the mouse is still our workhorse.

　　计算机鼠标是—个惊人的巧妙发明，它设计简单，但却能够使我们对计算机屏幕上的东西进 行非常有效的指挥。想想你可以用鼠标做的那些事情，比如复制和粘贴，以及绘画，甚至用新式 鼠标上的滚轮使网页上下滚动。大多数讦算机使用者天天用计算机，却没有想要了解一下鼠标的 i作原理，直到有一天它变脏了，而我们又必须学会如何对它进行清洁。我们会说话之前就已经 学会用手指东西，所以鼠标是一个很自然的指针设备。其他计算机指针设备还包括光笔、图形输 入板和触摸屏等，但鼠标仍然是我们的主要工具。

　　The computer mouse was invented in 1964 by Douglas Englehart of Stanford University. As computer screens became more popular and arrow keys were used to move around a body of text，it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful. The introduction of the mouse，with the Apple Lisa computer in 1983，really started the computer public on the road to relying on the mouse for routine computer tasks.3

　　计算机鼠标由斯坦福大学的道格拉斯.?恩格尔哈特在1964年发明。随着计算机屏幕越来越受 欢迎，而且箭头键可以在一个文本上随意移动，人们认识到一个能自由移动甚至能够选择文本的 游标装置将是非常有用的。19_83年鼠标的引进和苹果计算机丽莎的开始使用，使广大计算机用户 开始踏上一条依赖鼠标完成常规计算机工作的道路。

　　How does the mouse work? We have to start at the bottom，so think upside down for now. It all starts with the mouse ball. As the mouse ball in the bottom of the mouse rolls over the mouse pad，it presses against and turns two shafts. The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light-emitting diodes (LED) mounted on either side4. One LED sends a light beam to the LED on the other side. As the wheels spin and a hole rotates by，the light beam gets through to the LED on the other side. But a moment later the light beam is blocked until the next hole is in place. The LED detects a changing pattern of light，converts the pattern into an electronic signal，and sends the signal to the computer through wires in a cable that goes out of the mouse body. This cable is the tail that helps give the mouse its name. The computer interprets the signal to tell it where to position the cursor on the computer screen.

　　鼠标是怎样工作的?我们得从底部幵始，所以现在把鼠标倒过来看。一切都开始于鼠标球。 当鼠标底部的球在鼠标垫上滚动的时候，它压迫到两个滚轴并使其转动。这两个轴上有一些小孔, 并与滚轮相连。滚轮两边各有—个叫做发光二极管的小型电子发光器件。其中一个发光二极管向 另一个发出一个光束。当滚轮转过一个小孔时，光束通过小孔到达另一边的发光二极管。但稍后 该光束被阻塞，直到下一个孔转动到这个位置。发光二极管检测出光束的变化模式，将该模式转 换成电子信号，并通过一条延伸出鼠标的电缆将信号传输给计算机，这条像尾巴一样的电缆正是 鼠标得名的原因。计算机通过解读信号确定光标在计算机屏幕上的位置。

　　So far we have only discussed the basic computer mouse that most of you probably have or have used.5One problem with this design is that the mouse 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 this problem by having no moving parts.

　　到目前为止，我们只限于讨论大多数人应该拥有或用过的基本型的计算机鼠标。这样的设计 带来的一个问题是，滚球滚动时表面吸附的灰尘会使鼠标变脏，所以最终你必须对它进行清洁。较新的光电鼠标由于没有可移动的部件就避免了这一问题的产生。