题目内容
Section B
Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D.
听力原文： 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 do properly, a computer must be given instruction -- it must be programmed.
Computers cab be designed for many specialized purposes -- they can be used to prepare payrolls, guide airplane flights, direct traffic, even to play chess. Computers can play an essential role in modern automation in many places and factories throughout the world.
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【C16】
听力原文： The story of silk is a fascinating one. About 4,000 years ago the Chinese discovered the secret of the cocoon. No one knows exactly how or when this was made. One story says that a young princess was drinking tea in her garden and watching the silkworm spin cocoon. By chance one dropped into her tea, and the hot liquid softened it. When the girl tried to take the cocoon out of her tea. She pulled out a long silk thread.
The Chinese learned to weave the silk thread into cloth. For 2,000 years they were the only people who knew how to make silk. The Chinese merchants sold silk cloth throughout Asia and Europe and became rich. Silk was so expensive that it was called "the cloth of the Kings". Everyone wanted to learn how to make silk, but the Chinese kept the secret carefully guarded. Finally the secret was stolen. In the sixth century, two monks learned about the silk worms and their cocoons. They spent several years in China and finally found a way to take some worm eggs out of the country. The monks also carried bamboo canes. One day they hid some eggs in the hollow canes, and walked out of China with them. It is said that the development of the silk industry in other countries came from those few eggs which the monks had carried out of China.
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A．Because they are absent-minded in school.B．Because they are tired of learning it.C．B
【C12】
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