In the Caucasus region（高加索地区）, nearly 50 out of every 100,000 people live to celebrate their 100^th birthday, and many don’t stop at 100! By comparison, in America only 3 people in 100,000 reach 100. But these Caucasus people aren’t alone. The Pakistani Hunzas, who live high in the Himalaya Mountains, and the Vilcabambans of the Andes Mountains in Ecuador seem to share the secret of long life too.
　　These peoples remain healthy in body and spirit despite the passage of time. While many older persons in industrial societies become weak and ill in their 60s and 70s, some Caucasus people aged 110-140, work in the fields beside their great-great-grandchildren. Even the idea of aging is foreign to them. When asked, “At what age does youth end?” most of these old people had no answer. Several replied, “Well, perhaps at age 80.” The very youngest estimate was age 60.
　　What accounts for this ability to survive (live) to such old age, and to survive so well? First of all, hard physical work is a way of life for all of these long-lived peoples. They began their long days of physical labor as children and never seem to stop. For example, Mr. Rustam is 142 years of age. He remembers his life experience: the Crimean War of 1854; the Turkish War of 1878; the Bolshevik Revolution in 1917. His wife is 116 years old. They have been married for 90 years. Mr. Rustam has no plan of retiring from his life as a farmer. “Why? What else would I do?” he asks. Oh, he’s slowed down a bit. Now he might quit (stop working) for the day after 6 hours in the field instead of 10.
　　All these people get healthful rewards from the environment in which they work. They all come from mountainous regions. They live and work at elevations（海拔）of 5,000 to 12, 000 feet(1,660 to 4,000meters) above sea level. The air has less oxygen and is pollution-free. This reduced oxygen environment makes the heart and blood vessel（血管）system stronger.
　　Another factor（因素）that may lead to the good health of these people is their isolation. To a great extent, they are separated from the pressure（压力）and worries of industrial society.
　　Inherited（遗传的） factors also play some role. Most of the longest-lived peoples had parents and grandparents who also reached very old age. Good family genes may, therefore, be one factor in living longer.
　　Finally, although these three groups don’t eat exactly the same foods, their diets are similar. All of them eat little animal meat. Their diets are full of fresh fruits, vegetables, nuts, grains, cheese and milk. They never eat more food than their bodies need.
　　It is clear that isolation from urban pressure and pollution, clean mountain air, daily hard work, moderate diets, good genes, and a youthful approach to life all lead to the health and remarkable long life of all these people.
小题1: What is the main idea of this article?

A．Cause and effect of long-lived life.

B．People in the world enjoying a longer life.

C．Factors leading to the health and long life of people.

D．A description of several societies where people living a long life.

小题2: “The idea of aging is foreign to them” means that _________.

A．they don’t care much about their age

B．they have no idea of how old they are

C．they won’t say anything about their age until they are asked to

D．the idea of getting old has never come into their mind

小题3: How do you think the writer feels about these long-lived people?

A．He is much impressed with them.

B．He doesn’t care a bit about them.

C．He hopes that they will live a still longer life.

D．He doesn’t think their life is full of pressure and worries.