全新版大学英语听说教程第三册 Unit 14（在线收听）

Unit 14

Part B

Text 1

Genetic Engineering: for Better or Worse?

Technology is not only used to build spaceships and high-speed computers. It is also being used to create new plants and animals. This technology is known as genetic engineering. At the moment people all over the world are arguing about its benefits and drawbacks.

Some people are concerned that genetically engineered plants may harm the environment. Others are worried that they may be dangerous for people to eat.

For many years farmers have crossbred plants to create new types of plants that were, for example, bigger, stronger, or more attractive. Crossbreeding can take many years, however, and it is not precise. Now we can change exact sections of DNA, so the process is more accurate and faster.

There are many reasons for changing plants in this way. Some genetically engineered plants can live through frost or draught. As a result, farmers can make more profit because fewer plants will die. Other genetically engineered plants are more nutritious, have less fat, taste better or stay fresher than non-genetically engineered plants. This will allow people to buy better-quality fruit and vegetables.

Another advantage of genetically engineered plants is that some can resist natural pests such as viruses or insects. This reduces the amount of chemicals needed to kill pests, which is helpful to the environment.

However, genetically engineered plants can cause unexpected problems. Genetically engineered plants that resist pests may pass on that characteristic to a wild relative. This may cause the wild plant to spread fast, because pests are not naturally killing it. Genetically engineered plants can also harm animals. A type of corn has been developed that kills a species of insect that destroys it. The pollen from this corn, however, can also kill monarch butterflies, which do not harm the corn.

Genetic engineering is a very new science and we have a lot to learn about the good it can do and the damage it can cause. The main concern is that not enough tests are being done to ensure it is safe.

Statements:

1. Genetic engineering is a technology which is being used to _______.

2. Crossbreeding takes a _______ compared with genetic engineering.

3. According to the passage, genetic engineering enables plants to survive with little _______.

4. Genetic engineering can help farmers _______.

5. According to the passage, one of the problems caused by genetic engineering might be_______.

Text 2

Bioethics

Man: I've just been reading this amazing article about genetic engineering. The things they can do now.

Woman: I know, it's frightening, isn't it?

Man: No, not a bit. I mean if we can produce fruit that doesn't rot, animals that eat less and produce more, what's so scary about that?

Woman: OK. But you know those new microorganisms that they are producing. Well, you only need a laboratory accident and the effects would be far more disastrous than AIDS, for instance.

Man: Why are you always so negative?

Woman: I'm not negative.

Man: Soon I'll be able to have a genetic screening done and they'll be able to tell me what diseases I'm likely to have.

Woman: OK. But what if they tell you you're going to have a disease for which there's currently no known cure? That's not going to be much help, is it?

Man: Yeah, but if I know it's hereditary then I might think twice before having any children.

Woman: But you know where all this is leading, don't you? To a revival of eugenics, like they're going to be able to remove potentially harmful genes, like the ones that cause criminality, low IQ.

Man: And people like you with a bit of luck!

Woman: No, seriously. They can take a piece of someone's hair now and tell you all about that person's medical life. Now that could be an incredible invasion of someone's privacy.

Man: What do you mean?

Woman: Look. So at your job interview they ask you for a piece of hair, ring you up ten days later or whatever and tell you they don't want to employ you because you've got such and such a disease and you might die in five years.

Man: Don't be absurd.

Woman: I'm not being absurd.

Man: Do you think people would let them get away with that, huh? What is all this? It sounds like you've been reading 1984. Why don't you look on the practical side of things for a change?

Statements:

1. Both the speakers are against genetic engineering.

2. The woman sounds very optimistic about genetic engineering.

3. Genetic screening can tell you what diseases you may possibly develop.

4. Genes that cause criminality or low IQ can be removed from human bodies.

5. A job interviewer will resort to genetic screening to find out whether a job interviewee is healthy or not.

Part C

BBC under Fire over GM Crop Drama

The BBC has been accused of exciting the hysteria surrounding genetically modified crops with a new thriller. The criticism comes from Dr. Mark Tester, who was a scientific adviser on the forthcoming two-part drama, Fields of Gold. Dr. Tester has disowned the thriller, saying he was ignored when he told the BBC the plot was impossible.

Fields of Gold is to be broadcast on June 8 and 9 on BBC1. It follows two journalists investigating a mystery illness threatening the world, which turns out to have been spread by genetically modified wheat. Its central theme is the transfer of genes that are resistant to antibiotics from crops to a superbug.

The BBC said Dr. Tester changed his tune after originally telling them that the central theme was a possibility.

Dr. Tester, who is a lecturer at Cambridge University's Department of Plant Sciences, said, "The program makers had been blinded by their political agenda. It presents ridiculous errors of fact that give rise to anti-GM hysteria."

Dr. Tester said he had also been asked to look at the script before it went to production, and had pointed out the errors then, but was ignored.

However, a BBC spokeswoman said Dr. Tester told the program makers that the story was "unlikely" but "by no means impossible."

She added, "Like many thrillers, this is a fictional drama which does not mean to be a documentary. It examines the dramatic consequences of an extreme situation which is the subject of considerable debate amongst the scientific community."

Questions:

1. What is the name of the BBC drama?

2. When would it be broadcast?

3. What were the two journalists investigating in the drama?

4. What was the cause of the illness described in the drama?

5. What did Dr. Mark Tester think of the plot of the drama?

6. What did the BBC say about Dr. Tester?

7. What would the drama give rise to according to Dr. Tester?

Part D

Making a New Mosquito

Bloodsucking mosquitoes are perhaps Earth's most persistent pest, delivering malaria, yellow fever and a host of other diseases each year to more than half a billion people and killing between 2 million and 3 million. Numerous gallons of pesticides are sprayed each year in an effort to wipe out the tiny beasts. But the results have not been good. Many species of mosquitoes have become resistant to insecticides.

For nearly two decades scientists have been thinking of creating a designer mosquito that would have no ability to spread diseases. Finally in 1998, using technologies developed in genetic engineering, scientists succeeded in producing a new type of mosquitoes with red eyes. These mosquitoes not only look different but act in a different way. Every time they suck blood, a substance that recognizes bacteria and kills them will be produced.

The major challenge for scientists today is to create a species of mosquitoes that are incapable of transmitting malaria. For this they will have to turn their attention from the laboratory species to malaria-causing species in the wild.

As scientists move closer to their goal, they are facing a growing argument over whether it is practicable or wise to create such genetically engineered creatures and set them loose in the environment. One of the problems is that genetically engineered mosquitoes would need to be created for each of the estimated 100 species that carry illnesses that affect humans. Furthermore, strains of these mosquitoes vary from place to place. Even though these problems can be solved, where is the village or town that wants a million or so biting mosquitoes released?

Statements:

1. Pesticides have gradually become ineffective against many species of mosquitoes.

2. Scientists have been planning to create a designer mosquito to kill existing mosquitoes that spread diseases.

3. It's rather difficult for scientists to put their ideas into practice because mosquitoes are very small.

4. Using GE technology, scientists succeeded in creating a lab mosquito that is blind.

5. The new mosquitoes will soon be set loose in the environment.

6. Many people consider it unwise to create genetically engineered mosquitoes.

7. It's a big problem having to create genetically engineered mosquitoes for every species of disease-spreading mosquito.