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新视野大学英语第三版视听说教程第4册unit8答
案
Uint8 II. Basic Listening Practice 1. Script M: Scentists claim the world population has 99.5% of the same DNA. W: But this doesn?t tell us t here is no such thing as race. Q: What is true of the DNA of difference races? 2. Script W: With the advent of the genetic map we know where everything is, but do we know where to g o with it? M: Your map seems to differ largely from my geographical map! Q: What does the man imply? 3. Script M: As you know, it has taken millions of years of evolution and natural selection to get us where we are today. W: Yes, but now that we have genetic engineering, we seem to have decided that we want to be God. Q: What does the woman imply? 4. Script M: I think the research into cloning will lead us into dangers, filling us with false hopes of perfection. W: It?s too late to turn back the clock. We?ll just have to depend on common sense to solve uncommon problems. Q: What does the woman mean? 5. Script W: In America, many prisoners are having their cases reviewed, and some have even been freed t hrough DNA testing. M: Except for the ones whose death sentence has already been carried out. Q: What can we learn about DNA testing from the
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dialog? Keys: 1.B 2.C 3.D 4.A 5.C III. Listening In Task 1: Stem Cell Research Script Gregory: The Republican party in America is opposing stem cell research. I find it hard to beli eve that in this day and age, someone would do that. Lillian: Stem cell research sounds pretty impressive, I?ll admit. But just what is it? Gregory: Well, a stem cell is a special type of cell. It is a general cell that, when it devides, can become any sp ecific type of cell. Lillian: You mean, a stem cell can become a heart cell? Or a brain or a kidney cell? Gregory: That? s about it. Stem cells are a part of the body?s maintenance and repair system. When they div ide, they can become any cell type. Lillian: I guess there would be some tremendous medical advantages in that sort of research. Gregory: You?ve said a mouthful. Recently, scientists were able to help a man who lost a jaw bone for cancer. They recreated bone material for his jaw from stem cells. What it means is that since the new bone was created out of the person?s own cells, there was no problem with rejection because the DNA was the same. Lillian: I bet the person was delighted. Why would anyone oppose that sort of research? It would seem to have endless potential to benefit the human race. Gregory: I agree, but there are people who think we should not interfere with nature and manipulate “what is
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natural”.
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Lillian: It?s easier to hold such a narrow view if you?re not in a position to need the benefits of th e research. If you?re missing a jawbone because of cancer, you probably support the research. 1. What is the passage mainly about? 2. Who is against stem cell research? 3. What is special abo ut a stem cell? 4. When can a stem cell become another cell type? 5. According to the passage, why do some people oppose stem cell research? Keys: 1.B 2.A 3.A 4.A 5.D Task 2: The Improvement of Rice Script Scientists now know a lot more about a grain that people have eaten for ten thousand years. (S1) Research teams around the world have completed a map of the (S2) genes of rices. The findings a ppeared last week in the (S3) journal Nature. The aim is to speed up the improvement of rice. The scientists (S4) warn that the kinds of rice pla nts used now have reached the limit of their (S5) productivity. Yet world rice production must (S6) grow by an estimated 30 percent in the next twenty to meet demand. By 2025, as many as 4.6 bil lion people will depend on rice for (S7) survival. There is a lot of pressure on breeders to improve the crop, and the rice genome is a valuable tool to do that. (S8) Plant breeders have already used preliminary information from the rice genome to create experimental strains of rice that better re sist cold and pests.
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The researchers also say rice is an excellent choice for genetic mapping and engineering. Rice gen es have only about 390 million chemical bases. That maight sound like a lot. But other major food grains have thousands of millions. (S9) The new map could better explain more than just rice. Ric e shares a common ancestor with other cereal crops. Because rice is the first cereal crop to be full y analyzed, researchers expect that sufficient knowledge of its genetic information will reveal the heredity of more complex grains, including corn, wheat and barley. (S10) While significant progress has been made in the analysis of the rice genome, the mapping o f human genes is also making headway. When scientists can identify and manipulate genes that c ause certain diseases, mankind will cure them easily. The human genetic map may help us control a person?s height, weight, appearance and even length of life. Task3: The First Cloned Cat Script In the age-old battle of cats and dogs, score one for the cats. Researchers at Texas A&M Universit y recently announced that they have successfully cloned a cat name Rainbow—the first pet ever c loned—after several years of unsuccessful efforts to clone a dog name Missy. The ork, financed by a company hoping to provide pet-cloning services
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新视野大学英语第三版视听说教程第4册unit8答案
