参考答案 - 选修第一册第二单元
UNIT 2 LOOKING INTO THE FUTURE
Reading and Writing
① Read the text. Where do you think this text might come from? ldentify its purpose and possible audience.
CLONING: WHERE IS IT LEADING US?
When it was announced in 2018 that the Chinese Academy of Sciences in Shanghai had created the world's first cloned monkeys, Zhongzhong and Huahua, heated discussions followed online. In fact, cloning has always been with us. It is a way of making an exact copy of another animal or plant. It happens in plants when gardeners take cuttings from growing plants to make new ones. It also happens in animals when identical twins are produced from the same egg. These are both examples of natural clones.
Cloning has two major uses. First, gardeners use it to produce large quantities of plants for sale. Second, it is valuable for research on new plant species and for medical research on animals. Cloning plants is fairly straightforward, while cloning animals is much more complicated and difficult. Over the years, many scientists failed in their attempts to clone animals, but their determination and patience paid off in 1996 with a breakthrough—the cloning of Dolly the sheep.
The sheep cloning procedure works like this:
● Female sheep A provides an egg cell.
● The nucleus is removed from the egg cell.
● The egg cell is ready for a new nucleus.
● Female sheep B provides a somatic cell (体细胞) for the clone. The nucleus of this cell contains all the genes needed to produce a new sheep.
● The nucleus is taken out of the somatic cell.
● The somatic cell nucleus from sheep B and the egg cell from sheep A are joined.
● The cell divides and grows into an embryo.
● The embryo is put into female sheep C, who becomes the carrier of the clone.
● The lamb which is born is the clone of sheep B. It is in every way identical to sheep B, but younger.
With the advances of scientific research, cloning will have several major uses in the future. For one thing, it could be used to breed animal species which are endangered, or even bring back species which are now extinct. For another, it could be used to grow human organs or tissue in animals, which could be used for human organ transplants or medical treatments. Finally, cloning could be used to breed animals that will provide us with higher quality meat, milk, or eggs.
While there are technical issues that need to be worked through to make widespread cloning possible, the biggest concerns are moral. For example, if scientists brought an extinct animal back into existence, it would probably end up living in a zoo. That is not very good for the animal. Even worse for the animal is using it as a source of organ transplants—because it will be injured or even die. In addition, many people worry that eating animal products that result from cloning might be harmful to our health over time. The possibility of using cloning to produce human beings is an even bigger concern. What would happen if such knowledge ended up in the wrong hands?
When it comes to cloning, we wonder, ultimately, whether cloning will help or harm the world. No doubt, we will be talking about this question for a long time to come.
② Answer the questions using information from the text.
1 What are the two examples of natural clones?
2 What are the two main uses for clones today?
3 What future medical uses does cloning have?
4 Why might cloning an extinct animal be a bad idea?
5 Why do many people worry about cloned food?
③ Match the topics with the paragraphs.
Paragraph 1
A Possible uses of cloning in the future
Paragraph 2
B Whether cloning is good or bad
Paragraph 3
C Current uses of cloning
Paragraph 4
D What cloning is
Paragraph 5
E How cloning a sheep works
Paragraph 6
F Moral and ethical concerns about cloning
④ Discuss the following questions in groups.
1 What are the moral issues involved with cloning?
2 What does the author mean by "What would happen if such knowledge ended up in the
wrong hands?"
3 What moral concerns—if any—do you have regarding cloning? How important are these
issues to you? Why?
⑤ Imagine that you are a scientist and that you have the choice to clone or not to clone a particular animal species. Write a report about your choice.
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第二单元 展望未来
Suggested Answers
Activity 1
It appears to be a feature article from a newspaper, meant for general audiences to introduce cloning and raise their concerns.
Activity 2
1 It happens in plants when gardeners take cuttings from growing plants to make new ones. It also happens in animals when identical twins are produced from the same egg.
2 First, gardeners use it to produce large quantities of plants for sale. Second, it is valuable for research on new plant species and for medical research on animals.
3 It could be used to breed animal species which are endangered, bring back species which are now extinct, or grow human organs or tissues in animals, which could be used for human organ transplants or medical treatments.
4 If scientists brought an extinct animal back into existence, it would probably end up living in a zoo.
5 Many people worry that eating animal products that result from cloning might be harmful to our health over time.
Answers
Activity 3
Paragraph 1: D; Paragraph 2: C;
Paragraph 3: E; Paragraph 4: A;
Paragraph 5: F; Paragraph 6: B;
Suggested Answers
Activity 4
1 I think one moral issue is that the cloning animals would be treated as tools for science instead of living creatures and discarded after tests are done. It becomes even more complicated when we concern about human cloning. There may be moral issues of whether human clones should have the same human rights and whether they have the same consciousness as oniginal humans.
2 It may be used for bad purposes. It has already been suggested that cloned organs and tissue could be produced so that they could later be harvested for commercial purposes.
3 One big moral issue is that many people regard possible human clones as exact replicas of the original humans in every way (e.g., same personalities and identities), while such clones would be like twins of the original humans, but with their own personalities and identities. By regarding human clones as mere replicas, their humanity would be denied and this could result in all kinds of mistreatment.
Activity 5
Last year our team made an amazing find of Tyrannosaurus Rex's DNA encased in amber. In theory, this could be used to clone T. Rex, and bring this long-extinct dinosaur species back to life. However, in the end our team decided to give up this idea.
There are several reasons for this decision. First, we don't know enough about T. Rex, so we are not able to take care of such a creature appropriately. What can it eat, for example? Even though we may have some ideas of what T. Rex ate long ago, this food may no longer exist now. We also know very little about what kind of living environment a T Rex needs. Without proper food or living environment, it is quite possible that the animal would get ill or die before we find answers to these questions. Second, the DNA is not quite complete. This raises not only the possibility of failure in cloning it, but also that even if we succeeded, it would not be all that healthy. Since we are dealing with DNA that is millions of years old, it is probable that the clone will suffer abnormalities and live only for a short time and in pain. There are just too many unknowns.
Though we do not plan on using the DNA to make a clone, it is still quite useful for study, and there are many things we hope to learn from it. Perhaps in the future, scientists will have a better basis of knowledge with which cloning a T. Rex will become a reality. It is just not the time right now.
