【题目】In general, people are living longer now. Discuss the causes of this phenomenon. Use specific reasons and details to develop your essay.

　　21. Living Longer

　　In the past it was not uncommon for a man to die at forty, having lived a full life. But now we consider a lifespan of forty years to be very short. It is not unusual for people to live into their eighties and nineties, and some even reach 100. What's more, people are living long, healthy lives and are active well into their "golden years".

　　Mankind's longevity is due mainly to advances in science and technology. Medical breakthroughs have eradicated many fatal diseases that were once common. Perhaps more importantly, better general health means that people are less likely to contract infections in the first place. Better health also helps people prevent slowly debilitating conditions, such as heart disease, which can take their lives at an early age. And as civilization has advanced, our living environment and sources of food have become more sanitary. Furthermore, work is now safer and not as taxing on the human body. We do not wear out after just a few years of very hard work.

　　There are many reasons why people are now living longer than ever before. But what is more important is that they are living better as they live longer. It is my opinion that we have scientific and technological developments to thank for this progress.

　　【注释】

　　lifespan n.寿命what's more而且

　　golden years黄金时代；退休期(多指65岁以上)

　　mankind n.人类longevity n.长寿

　　advance n./v.进步breakthrough n.突破

　　eradicate v.根除fatal adj.致命的

　　contract v.感染infection n.传染病

　　debilitate v.使衰弱condition n.身体状况

　　civilization n.文明sanitary adj.卫生的

　　taxing adj.累人的；繁重的

　　wear out使筋疲力尽progress n.进步