【正文】 om, and the first space flight, Dolly’s appearance has generated a long list of difficult puzzles for scientists, politicians, and philosophers. And wild questions on the topic of cloning continue to mount. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Structural Analysis? 句型 Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 Para. 4 Why would anyone want to clone a human being in the first place? Para. 5 The human cloning situations that experts consider most frequently fall into two broad categories: 1) parents who want to clone a child, either to provide transplants for a dying child or to replace that child, and 2) adults who for a variety of reasons might want to clone themselves. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 Para. 6 Will it be possible to clone the dead? Para. 7 Perhaps, if the body is fresh, says one expert. The cloning method used requires bining an egg cell with the nucleus of a cell containing the DNA of the person to be cloned. (DNA is a very long, ribbonlike molecule that contains our geic information.) And that means that the nucleus must be intact. Cells die and the cell nucleus begins to break apart after death. But, yes, in theory at least it might be possible. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 Para. 8 Would a cloned human be identical to the original? Para. 9a Identical genes don’t produce identical people, as anyone who knows a set of identical twins can tell you. In fact, twins are more alike than clones would be, since they have at least shared the same environment within the mother, are usually raised in the same family, and so forth. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 Para. 9b Parents could clone a second child who resembled their first in appearance, but all the evidence suggests the two would have very different personalities. Twins separated at birth do sometimes share personality characteristics, but such characteristics in a cloned son or daughter would only be reminders of the child who was lost. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 Para. 10a Even in terms of biology, a clone would not be identical to the ―master copy‖. The clone’s cells, for example, would have energyprocessing machinery that came from the egg, not from the person who was cloned. But most of the physical differences between originals and copies are so minor that detection of them would require a sophisticated laboratory. The one possible exception is bearing children. 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Para. 10b The scientists responsible for the successful cloning are not sure that Dolly will be able to have lambs. They will try to find out once she’s old enough to breed. Para 11 What if parents decided to clone a child in order to harvest organs? Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Para. 12 Most experts agree that it would be psychologically harmful if a child sensed he had been brought into the world simply as an organ donor. But some parents already produce second children with nonfatal transplants in mind, and many experts do not oppose this. Cloning would increase the chances for a tissue match from 25 percent to nearly 100 percent. Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Para. 13 If cloned animals could be used as organ donors, we wouldn’t have to worry about cloning twins for transplants. Pigs, for example, have organs similar in size to humans’. But the human body attacks and destroys tissue from other species. To get around that, one pany is trying to alter the pig’s geic code to prevent pig organs from being attacked. If the pany’s technicians succeed, it may be more efficient to produce such pigs by cloning than by current methods. Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading 句型 Para. 14 How would a human clone refer to the donor of its DNA? Para. 15a ―Mom‖ is not right, because the woman who supplied the egg and gave birth to the infant would more appropriately be called Mother. ―Dad‖ isn’t right, either. A traditional father supplies only half the DNA in a child. Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading Para. 15b Judith Martin, in her writings under the name of ―Miss Manners‖, suggests the phrase, ―Most honored sir or madam‖. Why? ―One should always respect one’s ancestors,‖ she says, ―regardless of what they did to bring one into the world.‖ Back 預(yù)習(xí) 小結(jié) 導(dǎo)入 寫作 課文閱讀 隨 筆 課文縮寫 結(jié)構(gòu)分析 Text Analyzing and Reading 句型 Para. 16 That still leaves some confusion over vocabulary. The editorial director of one dictionary says that the noun ―clonee‖ may sound like a good term, but it’s not clear enough. Instead, he prefers ―o