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1、Uint8II. Basic Listening Practice1. Script M: Scentists claim the world population has 99.5% of the same DNA.W: But this doesnt tell us there is no such thing as race.Q: What is true of the DNA of difference races?2. ScriptW: With the advent of the genetic map we know where everything is, but do we
2、know where to go with it?M: Your map seems to differ largely from my geographical map!Q: What does the man imply?3. ScriptM: 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 d
3、ecided that we want to be God.Q: What does the woman imply?4. ScriptM: I think the research into cloning will lead us into dangers, filling us with false hopes of perfection.W: Its too late to turn back the clock. Well just have to depend on common sense to solve uncommon problems.Q: What does the w
4、oman mean?5. ScriptW: In America, many prisoners are having their cases reviewed, and some have even been freed through 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 dialog?Keys: 1.B 2.C 3.D 4.A 5.CIII. Listening
5、InGregory: The Republican party in America is opposing stem cell research. I find it hard to believe that in this day and age, someone would do that.Lillian: Stem cell research sounds pretty impressive, Ill admit. But just what is it?Gregory: Well, a stem cell is a special type of cell. It is a gene
6、ral cell that, when it devides, can become any specific type of cell.Lillian: You mean, a stem cell can become a heart cell? Or a brain or a kidney cell?Gregory: Thats about it. Stem cells are a part of the bodys maintenance and repair system. When they divide, they can become any cell type.Lillian:
7、 I guess there would be some tremendous medical advantages in that sort of research.Gregory: Youve said a mouthful. Recently, scientists were able to help a man who lost a jawbone for cancer. They recreated bone material for his jaw from stem cells. What it means is that since the new bone was creat
8、ed out of the persons 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
9、 we should not interfere with nature and manipulate “what is natural”.Lillian: Its easier to hold such a narrow view if youre not in a position to need the benefits of the research. If youre missing a jawbone because of cancer, you probably support the research.Keys: 1.B 2.A 3.A 4.A 5.DTask 2: The I
10、mprovement of RiceScientists 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 appeared last week in the (S3) journal Nature.The aim is to speed up the improvement of ric
11、e. The scientists (S4) warn that the kinds of rice plants 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 billion people will depend on rice for (S7) survival. T
12、here 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 resist cold and pests.The researchers also say rice is a
13、n excellent choice for genetic mapping and engineering. Rice genes 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. Rice shares a common ancestor with other cer
14、eal crops. Because rice is the first cereal crop to be fully 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
15、genome, the mapping of human genes is also making headway. When scientists can identify and manipulate genes that cause certain diseases, mankind will cure them easily. The human genetic map may help us control a persons height, weight, appearance and even length of life.Task3: The First Cloned CatI
16、n the age-old battle of cats and dogs, score one for the cats. Researchers at Texas A&M University recently announced that they have successfully cloned a cat name Rainbowthe first pet ever clonedafter several years of unsuccessful efforts to clone a dog name Missy.The ork, financed by a company hop
17、ing to provide pet-cloning services to wealthy owners, adds cats to a growing list of successfully cloned animals that includes pigs, sheep, cattle and mice.The success demonstrates cloning is a technology that could be transferred to other animal families as well. The accomplishment may provide new
18、 tools for studying diseases such as cats AIDS, a valuable research model for AIDS in humans.Research into animal cloning remains an important scientific alternative until the issue of human cloning is settled. And that seems unlikly in the immediate future, for it involves religious and moral princ
19、iples. There are, for example, groups that insist no one should be allowed to take on the role of God the Creator.To create cloned cat embryos for the experiment, researchers transferred DNA from adult cat cells into egg cells stripped of their own genetic information. Out of 82 attempts with cloned
20、 embryos, one attempt resulted in a failed pregnancy, and another yielded a kitten named CC, delivered from a surrogate mother on December 22. The kittens name refers to “Carbon Copy” and “Copycat”, the name of the cloning project.Cloning attempts with dogs have proven unsuccessful in part because d
21、ogsreproductive cycles are more complicated.The technique may also work with endangered cats such as the African wildcat, fishing cat and blackfooted cat.Ironically, the increased knowledge of cat reproduction may best be suited for developing cat contraceptives to control the U.S. cat population.Ke
22、ys: 1.A 2.B 3.C 4.B 5.CIV. Speaking OutWhy are people protesting against genetically modified foods?Susan: With so many people suffering from malnutrition around the world, why are people protesting against genetically modified foods?Chris: Some people are protesting about genetically modified foods
23、, but even more people are protesting the fact that processed foods containing these ingredients arent labeled.Susan: But why should they be labeled?Chris: Not everyone is sure that genetically modified foods are safe. They want to be certain that biotech foods have the sme composition as organic fo
24、ods.Susan: But there are more urgent problems in this world. Many people are dying of starvation.Chris: But those who arent starving may want genetically modified foods to be labeled so they know what foods they should andd shouldnt eat.Susan: You know, I heard of a genetically modified fish that gr
25、ew to be ten times its normal size.Chris: That sure sounds abnormal.Susan: Yeah, it does sound a bit strange , but that fish could feed ten times as many people.Chris: Youre right; genetically modified food might help solve world hunger. But I think we have a right to know what we are eating.MODEL2
26、Do you think the cloning of humans should be forbidden by law?Susan: After the cloning of Dolly the sheep, I think human cloning is next.John: Whoa. I have some reservations about it. There are stll many scientific problems to solve before human cloning starts.Susan: Theres an easier way. The Clonai
27、d Company says theyve cloned humans.John: Oh, my God! These guys claim aliens from another planet taught them humancloning.Susan: A woman gave them half a million dollars to clone her dead daughter.John: Clearly that woman doesnt know much about cloning. How risky it is!Susan: I know its inefficient
28、. It took 276 tries to produce Dolly. But why is it risky?John: Cloned animals grow abnormally large and age unnaturally fast.Susan: In other words, that woman may not be happy with her cloned daughter.John: Then there are the emotions. No one knows if cloning damages the mind.Susan: Do you think th
29、e cloning of humans should be forbidden by law?John: To my mind, the cloning of human organs shouldnt be prohabited. It may help solve medical problems.Susan: I see your point: cloning should be regulated if its to benefit humanity.MODEL3 Is it interfering with nature?Nora: Some religious groups are
30、 opposed to genetic research. They believe its interfering with nature.John: I know. But nature can be pretty hard-nosed too, so we often need to interfere with herwe build dams to control flooding.Nora: Therere many diseases that are a part of nature, and they cause people a great deal of misery: c
31、ancer and diabetes, for example.John: A better understanding of the genetic code that controls our body would be a great help in curing many diseases.Nora: The project to map the human genetic codewhats that called?John: The genome project. As you say, it has tremendous promise to make our lives bet
32、terjust in the ability to identify and correct genetically-caused diseases like Alzheimers.Nora: Some diseases like cancer are also believed to have a genetic switch.John: Thats right, and once researchers identify the switch, perhaps they can turn off cancer or Alzheimers.Nora: People are also conc
33、erned that science will enable us to determine such qualities as intelligence and height.John: You know its going to happenits just a matter of when.Nora: Imagine if everyone was a combination of Yao Ming and Albert Einstein.John: But what if they get it wrong, and you wind up with Yao Mings knowled
34、ge of nuclear physics and Albert Einsteins height?Nora: All those religious groups would say that it served you right.Now Your TurnSAMPLE DIALOGJane: Some countries are suffering from crop failure and famine, but why do they refuse genetically modified crops and foods?Bob: And many Europeans insist
35、that processed foods containing GM ingredients be labeled.Jane: Why should they be labeled?Bob: Not everyone is sure that genetically modified foods are safe. They want to certain that biotech foods have the same composition as traditional foods.Jane: But there are more urgent problems in this world
36、. Many people are dying of famine.Bob: But those who arent hungry may want all genetically modified products to be labeled so they know exactly what theyre eating.Jane: You know, Ive heard of a GM fish that was ten times larger than a normal fish.Bob: That really sounds abnormal.Jane: Some famine-st
37、ricken people are afraid GM crops will overpower and eliminate their native crops.Bob: Sounds alarming.Jane: Yeah, but GM foods can feed many people.Bob: Youre right; they could solve the problem of starvation in the world. But I think we have a right to know what we are eating. GM food should be la
38、beled.V. Lets TalkCorrespondent: In the U.S. what percentage of people support biotech crops? And do those who support biotech crops also eat biotech foods? What percentage of food on the market has genetically modified ingredients?Professor: U.S. consumers have been exposed to a very effective anti
39、-biotechnology propaganda campaign for the last few years, but according to polls, over 70% support biotechnology. For example, in a recent referendum in Oregon, voters rejected a proposal to require special labels on all products containing biotech ingredients by an overwhelming 73% to 27%. Thats p
40、robably because consumers know that we have an effective administrative system. Many may also know that 70-80% of the processed food products on supermarket shelves contain one or more ingredients from biotech crops. All Americans eat biotech foods unless they deliberately seek out products that are
41、 labeled otherwise. Evidence suggests that this is less than 5% of consumers.Correspondent: Chinese scientists have used biotechnology to create a new type of tomato, which contains the vaccine against hepatitis B. Whats your take on this?Professor: Its a great example of how this technology can be
42、used to save lives, ease pain and suffering and improve the human condition. How can anyone be opposed to that? My only hope is that the clinical trials of this new tomato go well, and that it is quickly delivered to health-care providers who will use it to vaccinate people against hepatitis. By the
43、 way, please note that I do think that such new pharmaceutical foods need to be handled as medicines by professionals and not as conventional foods. You will never see these tomatoes in the supermarket. In a sense, the tomato plant is just being used to manufacture a vaccine in a very safe and econo
44、mical manner.U.S. Consumers attitude to BiotechOver 70% of U.S.consumers support biotechnology.ExamplesIn a recent referendum in Oregon, voters rejected a proposal to require special labels on all products containing biotech ingredients by an overwhelming 73% to 27%.Chinese Progress in BiotechChines
45、e scientists have used biotechnology to create a new type of tomato, which contains the vaccine against hepatitis B.Significance of the ProgressThis technology can be used to save lives,ease pain and suffering and improve the human condition.The Professors AdviceI do think that such new pharmaceutic
46、al foods need to be handled as medicines by professionals and not as conventional foods.VI. Further Listening and SpeakingConfident enough to control your fate?Some people are born with the belief that they are masters of their own lives. Others feel they are at the mercy of fate. New research shows
47、 that part of those feelings are in the genes.Psychologists have long known that people confident in their ability to control their fates are more likely to adjust well to growing old than those who feel they drift on the currents of fate.Two researchers who questioned hundreds of Swedish twins repo
48、rt that such confidence, or lack of it, is partly genetic and partly drawn from experience.They also found that the belief in blind lucka conviction that chance plays a big role in lifeis something learned in life and has nothing to do with heredity.The research was conducted by Nancy Pedersen, a professor of psychology at the University of Southern California in Los Angeles. The results were recent