听力文摘：人类何以长寿?

Long Live Us

人类万岁

About a century ago, the average life-span for Americans was about 50 years. Today, the typical American lives for around seventy-eight years.

约一个世纪以前，美国的人均寿命是50岁左右。如今，美国一般都能活到78岁左右。

According to a German aging study, the maximum life span in industrialized countries has increased by two years every decade since the mid¹ 19th century. What accounts for such increased longevity²?

德国一项关于寿命的研究指出，19世纪中叶以来工业化国家人口的最高寿命增长迅速——每十年人们的最高寿命就会增长两岁。是什么让人们的寿命增长的如此之快呢？

Between 1900 and 1950, inventions such as refrigeration and sewage treatment meant that young people were able to survive longer. Moreover, medical breakthroughs helped contain diseases such as polio, which killed many children. These advances helped increase the average life span.

1900年至1950年期间，制冷技术及污水处理的发明便意味着年轻的一代能活得更久。再者，医疗水平的重大突破对一些疾病起到了很好的控制作用，例如夺去许多儿童生命的小儿麻痹症。社会的这些进步都有助于提高人类的平均年龄。

Medical discoveries after World War II tended to benefit older people. Treatments for heart disease, for example, have allowed the elderly to live longer on average. So does this mean that future medical breakthroughs will result in even longer average life spans, or have we reached our limit? Scientists disagree.

二战后的科学研究都倾向于“造福”老年群体。就拿对心脏病的治疗来说，就大大提高了老年人的平均寿命。那我们是不是就可以由此推出——日后的医学突破将会使人类的平均寿命再得到延长，或是，人类已经达到了生命的极限？科学家对此持否定看法。

Some argue that if science is one day able to eradicate³ disease and old-age infirmity, there will be virtually no limit on how long humans can live. Some even predict that by the year 2150, the average life span will have increased to around 120 years.

有人认为，如果科学能够消除一切疾病以及年老体衰，那么人类的寿命就没有了限度。更有甚者，有人预测到2150年，人类的平均寿命将会达到惊人的120岁。

Other life-expectancy⁴ researchers find that scenario⁵ highly unlikely. Our bodies' cells can keep reproducing for only so long before they peter out. Only when science finds a way to keep our cells dividing longer will we see another significant leap in life expectancy.

其他的寿命研究人员认为这样的假设是不可能的。人体细胞只能在细胞数量逐渐减少前不断进行复制。除非科学家们找到方法延长细胞分裂时间，人类的平均寿命才可能再有一次突飞猛进。

Still, with plenty of exercise and a healthy diet, those so inclined can always hope that they'll live long enough to break the record held by Jeanne Louise Calment of France, who lived to be 122.

当然，那些赞成此种观点的人也可以怀抱这样的一份希望——坚持锻炼，养成健康的饮食习惯，打破法国Jeanne Louise Calment老人122岁的长寿记录。

1 mid   

adj.中央的，中间的

参考例句：

• Our mid-term exam is pending.我们就要期中考试了。
• He switched over to teaching in mid-career.他在而立之年转入教学工作。

2 longevity   

n.长命；长寿

参考例句：

• Good habits promote longevity.良好的习惯能增长寿命。
• Human longevity runs in families.人类的长寿具有家族遗传性。

3 eradicate   

v.根除，消灭，杜绝

参考例句：

• These insects are very difficult to eradicate.这些昆虫很难根除。
• They are already battling to eradicate illnesses such as malaria and tetanus.他们已经在努力消灭疟疾、破伤风等疾病。

4 expectancy   

n.期望，预期，（根据概率统计求得）预期数额

参考例句：

• Japanese people have a very high life expectancy.日本人的平均寿命非常长。
• The atomosphere of tense expectancy sobered everyone.这种期望的紧张气氛使每个人变得严肃起来。

5 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。