We are born，we live，we age and we die. This is the natural cycle of human existence. The world record holder for the longest human life is Jeanne Louise Calment of France，who lived to 122 years and 164days. But what is the secret to along life?
Human beings are complex， and we live for a very long time，making studies of the process of ageing a serious challenge. Most of the research to date has therefore been done in animals. Two of the favorite species for these kinds of studies are Caenorhabditis elegans，a very tiny worm，and Mus musculus，the laboratory mouse. The worms generally live for just two or three weeks， while the mice have an up-per lifespan of around three years，and both have a lot of genes that are quite similar to our own. Using these models，researchers have i denied several possible candidates, including stem cell, calorie restriction(能量限制), and even some drugs, could hold off the ageing process.
After years of careful research，there is now a wealth of knowledge just waiting to be tested in people.We spoke to Brian Kennedy, CEO of the Buck Institute for Research on Ageing. “We're a nonprofit medical research institute that's focused on understanding ageing. We realized when the doors opened in1999 that ageing was the biggest risk factor behind all of the diseases that we care about, ”he explains.“I think the exciting thing that we have lea med over the past decade is that it's really possible to slow ageing in a mouse，or even in primates(灵长类动物) .The challenge now is to take that knowledge and apply it to humans.
5.The studies of ageing were performed in two special animals because______
A.their genes are similar to mankind's
B.their genes are easy to be tested
C.they have similar lifespans to mankind
D.they have the same genes as mankind
6.Which of the following can probably be used to prevent ageing proces ?
A.Animal genes.         B.Mus musculus：
C.Stem n cells.          D.Caenorhabditis elegans.
7.What can we learn from the last paragraph?
A.The study of ageing was started in 1999.       [
B.Is possible to slow ageing in some animals.
C.The study of ageing cant be tested in humans.
D.The study shows that slowing ageing in humans is a reality.
8.Whats Brian Kennedy's attitude towards slow ageing?
A.Critical      B.Negative   C.Indifferent    D.Positive
B【语篇解读】本文是一篇说明文。文章介绍了科学家们在研究延缓衰老方面所取得的成就和前景。
5.A 解析 根据文章第二段，and both have a lot of genes that are quite similar to our own.
6.C 解析细节理解题。根据文章第二段最后一句中“researchers have identified several possible candidates, including stem cells, calorie restriction(能量限制) , and even some drugs，could hold off the ageing process.”可知， 研究者确定了干细胞， 能量限制和一些药物能够抵抗衰老的过程。由此可知答案，故选C项。
7.B 解析细节理解题。根据文章最后一段倒数第二句“I think the exciting thing that we have learned over the past decade is that it's really possible to slow ageing in a mouse， or even in primates(灵长类动物).”可知，一些动物有可能延缓衰老的过程。
8.D 解析推理判断题。根据文章最后一段最后两句“I think the exciting thing that we have learned over the past decade is that it's really possible to slow ageing in a mouse, or even in primates(灵长类动物) .The challenge now is to take that knowledge and apply it to humans.”可知， Brian Kennedy认为，经过过去十年, 人们已经认识到一些动物延缦衰老是可能的, 现在的挑战就是取得那些知识，并应用于人类。由此可见，他对延缓衰老持肯定的态度。