六级考试阅读考前练习1

　　1 Computers have been taught to play not only checkers, but also championship chess, which is a fairly accurate yardstick for measuring the computers progress in the ability to learn from experience.

　　2 Because the game requires logical reasoning, chess would seem to be perfectly suited to the computer .all a programmer has to do is give the computer a program evaluating the consequences of every possible response to every possible move, and the computer will win every time. In theory this is a sensible approach; in practice it is impossible. Today, a powerful computer can analyze 40 000 moves a second. That is an impressive speed. But there are an astronomical number of possible moves in chessliterally trillions. Even if such a program were written , there is no computer capable of holding that much data.

　　3 Therefore, if the computer is to compete at championship levels, it must be programmed to function with less than complete data. It must be able to learn from experience, to modify its own programm, to deal with a relatively unstructured situationin a word, to think for itself . In fact, this can be done. Chess-playing computers have yet to defeat world champion chess players, but several have beaten human players of only slightly lower ranks. The computers have had programs to carry them through the early, mechanical stages of their chess games. But they have gone on from there to reason and learn, and sometimes to win the game.

　　4 There are other proofs that computers can be programmed to learn, but this example is sufficient to demonstrate the point. Granted , winning a game of chess is not an earthshaking event even when a computer does it . But there are many serious human problems which ban be fruitfully approached as games. The Defense Department uses computers to play war games and work out strategies for dealing with international tensions. Other problemsinternational and interpersonal relations , ecology and economics , and the ever-increasing threat of world faminecan perhaps be solved by the joint efforts of human beings and truly intelligent computers .

　　Notes

　　1. check:a game played on a checkerboard by two players ,each using 12 pieces

　　2. ecology:the relationship between organisms and their environment 生态关系，生态学