大学英语四级 听力 科普知识类原文及答案

Passage Two 科普知识类Do you have a tough math test coming up? Then listen to some classical piano music just before the test. You might end up with a higher score. Researchers at a university in California conducted an experiment. They asked a group of college students to listen to some piano music by a famous 18th century composer before taking a math test. They were surprised to find that the students' scores jumped 8 to 9 points. The music seems to excite nerve activity in the brain; similar to the activity that occurs when a person is figuring out a math problem. However, the scientists warn that before you get too excited about applying this method to your math test. You should remember that brain exciting effects last only 10 or 15 minutes. Would rock music work as well as the piano music did? No, the scientists say. In fact, the less complex music might even interfere with the brains reasoning ability.Questions 15 to 17 are based on the passage you have just heard.C15. What is this passage mainly about?A16. Why can classical music play a positive role in problem solving? B17. What is one of the findings of the research?2．Passage Three 科普知识类When a sleepy driver has trouble in keeping his eyes on the road and gets too close to another car, an alarm sound will warn the driver. If nothing is done, the car will automatically come to a stop and in this way prevent an accident. This is a new device which will soon be tested in an experimental car in Japan. The computer warning system keeps track of a driver's condition by monitoring his heart beat with signals transmitted from a band round his wrist. The wrist band records the driver's pulse which measures the heat beat. Each pulse in the wrist sends a signal to the computer. By analyzing the pulse rate, the computer can determine whether a driver is drunk, sleeping or ill. Devices in other parts of the car can also tell the computer if the car is too close to another vehicle or is moving dangerously. The computer will sound the alarm when a problem arises, and will automatically stop the car if the driver ignores the warning.Questions 18 to 20 are based on the passage you have just heard.C18. Why is a computer system installed in an experimental car?B19. What did the computer system do first when a problem arises?D20. What is special about the new computer system?Passage Three 科普知识类You can tell the age of a tree by counting its rings, but these records of trees’life really say a lot more. Scientists are using tree rings to learn what’s being happening on the sun’s surface for the last ten thousand years. Each ring represents a year of growth. As the tree grows, it adds a layer to its trunk taking up chemical elements from the air. By looking up the elements in the rings for a given year, scientists can tell what elements were in the air that year. Doctors Stevenson is analysing one element——carbon-14 in ring from both living and dead trees. Some of the rings go back almost ten thousand years to the end of the Ice Age. When Stevenson followed the carbon-14 trail back in time, he found carbon-4 levels change with the intensity of solar burning. You see the sun has cycles. Sometimes it burns fiercely and other times it’s relatively calm. During the sun’s violent periods, it throws off charged particles in fast moving strings called solar winds. The particles interfere with the formation of carbon-14 on earth. When there’s more solar wind activity, less carbon-14 is produced. Ten thousand years of tree rings show that the carbon-14 level rises and falls about every 420 years. The scientists concluded that the solar wind activity must follow the same cycle.A18. What is the purpose of the scientists in studying tree rings ﹖C19. What affects the amount of carbon-14 on earth ﹖D20. What do we learn from the passage about the solar wind activity ﹖4．Passage 3 科普知识类Many people catch a cold in the spring time or fall. It makes us wonder if scientists can send a man to the moon. Why can’t they find a cure for the common cold? The answer is easy. There’re actually hundreds of kinds of cold viruses out the re. You never know which one you will get, so there isn’t a cure for each one. When a virus attacks your body, your body works hard to get rid of it. Blood rushes to your nose and causes a blockade in it. You feel terrible because you can’t breathe well, b ut your body is actually eating the virus. Your temperature rises and you get a fever, but the heat of your body is killing the virus. You also have a running nose to stop the virus from getting into your cells. You may feel miserable, but actually your wonderful body is doing everything it can to kill the cold. Different people have different remedies for colds. In the United States and some other countries, for example, people might eat chicken soup to feel better. Some people take hot bath and drink warm liquids. Other people take medicines to relieve various symptoms of colds. There was one interesting thing to note. Some scientists say taking medicines when you have a cold is actually bad for you. The virus stays in you longer, because your body doesn’t develop a way to fight it and kill it.Questions 33 to 35 are based on the passage you have just heard.B Question 33: According to the passage, why haven’t scientists found a cure for the common cold?D Question 34: What does the speaker say about the symptoms of the common cold?A Question 35: What do some scientists say about taking medicines for the common cold, according to the passage?。