阅读理解。 Researchers found that people become happier and experience less worry after they reach the age of fifty. In fact, they say by the age of eighty-five, people are happier with their life than they were when they were eigh years old. The findings came from a survey of more than 340,000 s in the United States. The Gallup (民意调查)Organization questioned them by telephone in 2008. At that time, the people were between the ages of eighand eighty-five. The researchers asked questions about emotions like happiness, sadness and worry. They also asked aboutmental or emotional stress. Arthur Stone at Stony Brook University in New York led the study. His team found that levels of stresswere highest among s between the ages of twenty-two and twenty-five. The findings showed that stresslevels dropped sharply after people reached their fifties. Happiness was highest among the youngest s andthose in their early sies. The people least likely to report feeling negative emotions were those in their sies and eighties. Researchers say they do not know why happiness increases as people get older. One theory is that, as people grow older, they grow more thankful for what they have and have better control of their emotions. They also spend less time thinking about bad experiences. Professor Stone says the emotional patterns could be linked to changes in how people see the world, ormaybe even changes in brain chemistry. The researchers also considered possible influences like having young children, being unemployed or beingsingle. But they found that influences like these did not affect the levels of happiness and well-being related toage. The study also showed that men and women have similar emotional patterns as they grow older. However,women at all ages reported more sadness, stress and worry 1. We can learn from the research that ____. A. only when people get older will they feel happierB. stress levels among the youngest are the highestC. older people tend to be grateful D. older people usually have no worries