A. immeasurably B. replaced C. priority D. failing  E. frustratingly
F. potential  G. minor  H. trick  I. unrepaired J. prospect K. wiring

Scientific breakthroughs mean that life expectancy continues to rise every year. But the medical advances which now make it possible to think about living to a very great age --- if not forever --- also raise profound practical and ethical issues.   
Is immortality (永生) a realistic __41__? 

 Not for the foreseeable future. In last year’s Reith lectures, the gerontologist (老年病学家) Professor Tom Kirkwood firmly quashed (打消) the idea that genetic engineering might result in some kind of “fountain of youth”. Considering how __42__slow the battles against cancer, heart disease and strokes have been, he said, it is fanciful to imagine that we could conquer death. On the other hand, scientists do now understand more about why we age, and what can be done to slow down the process. “Our ancestral genes placed limited __43__on long-term maintenance and repair,” says Kirkwood. “Ageing comes about through the gradual build-up of __44__ faults in the cells and tissues of our bodies, not as the result of some active mechanism for death and destruction.” The __45__ , then, is to help the body repair the damage done by wear and tear.
How can that be done? 

 In many different ways, some of which are already pretty common. Organ transplants from pigs and monkeys are now old news --- the American politician Jesse Helms has just had a ten-year-old pig valve (瓣膜) in his heart __46__. Doctors have succeeded in __47__computerized implants directly to nerve fibres, allowing the deaf to hear, and there is hope that electrodes (电极) planted in the brain may soon offer hope for the blind to see. But the real __48__at the moment lies in the field of stem cells --- special cells that allow lizards (蜥蜴) to grow new tails and humans to grow new skin over __49__cuts. If scientists can learn how to control these cells, they could be used to reproduce parts of the body that are __50__.  

真相大白

41.J        42. E       43.C       44.I         45.H                        

46. B       47.K       48.F       49.G         50.D

名师把脉

步步为赢

41. prospect。解析：realistic为形容词，缺名词，prospect意为前景。该句意思是未来永生可以成为现实吗？

42. frustratingly。解析：how后面缺程度副词修饰形容词slow，对抗各类疾病的斗争缓慢，这是令人沮丧的事情。

43. priority。解析：形容词limited后缺名词，另外，注意“优先考虑”的表达——place/priority on/ upon sth.，平时要注意表达的积累。

44. unrepaired。解析：选择形容词修饰fault，出现老化是因为细胞和组织中未修复的“毛病”。

45. trick。解析：trick有计策的含义。Damage对应前句提到的fault，为同义转换。针对上述身体上的毛病，then引出解决方法就是修复这些问题。

46. replaced。解析：注意使役态have sth. done，由别人来做某事，这里是将人的心脏瓣膜和猪的替换，replace有替换的意思。

47. wiring。解析：首先succeed in doing sth.，这里选唯一一个v-ing无可厚非。从含义上来看，这个手术是将计算机植入体与神经纤维连线。

48. potential。解析：but有前后转折的逻辑，前面两个例子是通过植入物造福病人，给人带来希望，后一句话锋一转，指出真正的潜力蕴藏在自身的干细胞中。

49. minor 。解析：选择形容词修饰割伤cuts，干细胞让人类在轻微皮肤割伤后可以长出新的皮肤，运用常识也知道，大的伤害就要借助医疗的力量了。

50. failing。解析：与reproduce（重生）相对应，这里修饰定从先行词body是那些已损伤的机体，对failing的理解要到位，不是表面含义的失败，而是功能缺失或有毛病的。