答案与解析：

　　1.分析文章标题：(Do you)Find(发现，找到) Yourself Packing It On? Blame(责备) Friends(朋友)

　　Obesity can spread from person to person, much like a virus, researchers are reporting today. When one person gains weight, close friends tend to gain weight, too.

　　Their study, published in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003.

　　The investigators knew who was friends with whom as well as who was a spouse or sibling or neighbor, and they knew how much each person weighed at various times over three decades. That let them reconstruct what happened over the years as individuals became obese. Did their friends also become obese? Did family members? Or neighbors?

　　The answer, the researchers report, was that people were most likely to become obese when a friend became obese. That increased a persons chances of becoming obese by 57 percent. There was no effect when a neighbor gained or lost weight，however, and family members had less influence than friends.

　　It did not even matter if the friend was hundreds of miles away, the influence remained. And the greatest influence of all was between close mutual friends. There, if one became obese, the other had a 171 percent increased chance of becoming obese, too.

　　The same effect seemed to occur for weight loss, the investigators say. But since most people were gaining, not losing, over the 32 years, the result was, on average, that people grew fatter.

　　Dr. Nicholas A. Christakis, a physician and professor of medical sociology at Harvard Medical School and a principal investigator in the new study, said one explanation was that friends affected each others’ perception of fatness. When a close friend becomes obese, obesity may not look so bad.

　　“You change your idea of what is an acceptable body type by looking at the people around you,” Dr. Christakis said.

　　The investigators say their findings can help explain why Americans have become fatter in recent years �C each person who became obese was likely to drag along some friends!

　　Their analysis was unique, Dr. Christakis said, because it moved beyond a simple analysis of one person and his or her social contacts and instead examined an entire social network at once, looking at how a person's friend's friends, or influence on a person's weight or a spouse's sibling's friends, could have an influence on a person’s weight.

　　The effects, he said, “highlight the importance of contagion, that spreads through the network.”

　　Of course, the investigators say, social networks are not the only factors that affect body weight. There is a strong genetic component at work, too.

　　Science has shown that individuals have genetically determined ranges of weights, spanning perhaps 30 or so pounds for each person. But that leaves a large role for the environment in determining whether a person’s weight is near the top of his or her range or near the bottom. As people have gotten fatter, it appears that many are edging toward the top of their ranges. The question has been why.

　　If the new research is correct, it may say that something in the environment seeded what some call an obesity epidemic, making a few people gain weight. Then social networks let the obesity spread rapidly.

　　分析：“pack it on”的含义为“变得肥胖”，因此文章主题内容为“如果你发现自己变胖了， 你应该责怪你的朋友们”。

　　2.直接解题：

　　1. Who had the greatest (最大的，/伟大的， 非常的)influence on (有对...的影响)people who became obese?

　　A. their friends

　　B. their neighbors(邻居)

　　C. their family(家庭， 家庭的) members(成员)

　　D. their colleagues(同事)

　　1.A. 该题可根据文章主题(文章标题内容)“如果你发现自己变胖了，你应该责怪你的朋友们”直接判断答案。 也可以依据文章中的相关内容判定答案：利用备选项中的细节信息词(A：friends; B: neighbors; C: family members; D: colleagues)共同作为答案线索，在文章中查找答案相关句：

　　Obesity can spread from person to person, much like a virus, researchers are reporting today. When one person gains weight, close friends tend to gain weight, too.

　　Their study, published in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003.

　　The investigators knew who was friends with whom as well as who was a spouse or sibling or neighbor, and they knew how much each person weighed at various times over three decades. That let them reconstruct what happened over the years as individuals became obese. Did their friends also become obese? Did family members? Or neighbors?

　　(第一题答案相关句)(第4段)The answer(答案), the researchers(研究者) report(报告), was that people were most likely to (很可能...)become obese(肥胖的) when a friend (朋友)became obese. That increased(增加) a person’s chances of (...的机会/可能性)becoming obese by (了)57 percent(百分之). There was no effect(influence的近义词)(影响，实现) when a neighbor gained or lost weight(增肥或减肥)，however(然而), and family members had less (较少的， 不太，不(如))influence(影响) than friends.

　　答案相关句(第四段)说“提到研究者发现，当周围朋友发福时，人最容易发胖.而邻居则不会对人产生影响，甚至家庭成员的影响也不如朋友大。而关于同事的内容，文章中并没有提到。

　　2. Which of the following (下列哪个)statement(陈述，声明) about a friend's influence(影响) is false(错误的，假的， 人工的) according to (根据)the report(报告)?

　　A. Friends had more influence (影响)than(比) family members(家庭成员) on people who became obese.

　　B. Even if (即使)the friend lives far away(遥远), the influence still (仍然，更)remained(继续， 留下)

　　C. People were not likely to (可能...)lose weight (减肥)when they have skinny(皮包骨的) friends.

　　D. The greatest influence of all(全部) was between close(近的, 紧密的, 亲密的) mutual(共有的， 相互的) friends.

　　2.C. 可以借助文章主题或接着解答上一题所获得的相关信息直接判断C错误。 也可以借助文章中的相关内容判断答案：

　　Obesity can spread from person to person, much like a virus, researchers are reporting today. When one person gains weight, close friends tend to gain weight, too.

　　Their study, published in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003.

　　The investigators knew who was friends with whom as well as who was a spouse or sibling or neighbor, and they knew how much each person weighed at various times over three decades. That let them reconstruct what happened over the years as individuals became obese. Did their friends also become obese? Did family members? Or neighbors?

　　(第一题答案相关句)The answer, the researchers report, was that people were most likely to become obese when a friend became obese. That increased a persons chances or becoming obese by 57 percent. There was no effect when a neighbor gained or lost weight，however, and family members had less influence than friends.

　　(第二题答案相关句)It did not even(甚至) matter(有关系。 事情， 物质)if (是否， 如果)the friend was hundreds of miles away(在远处， 到远处), the influence remained(继续). (与选项B内容一致)And the greatest influence of all was between close (亲密的)mutual(相互的) friends(与选项D内容一致). There, if one became obese, the other had a 171 percent increased chance of becoming obese, too.

　　A选项说的是“朋友产生的影响大于庭成员”，该选项内容与第一题答案相关句内容一致; B选项也是正确的， 因为第五段第一句话提到，即使朋友远在千里之外，这种影响仍然存在：第五段第二句特合D选项的愈思：那些关系亲密的朋友产生的影响最大。因此只有C不正确。

　　3. According to (根据)Dr.(博士， 医生) Nicholas A. Christakis, what is the explanation for (对...的解释)friends being the greatest influence?

　　A. Friends usually(通常) spend(花费(时间/金钱)) a lot of (很多的)time together(一起，共同).

　　B. Friends share(分享， 共有) similar(相似的) eating habits(饮食习惯).

　　C. Friends are more important (更重要的)than family members.

　　D. Friends affected(影响) each others(彼此)’ feelings(感觉， 知觉)of fatness(肥胖)

　　3.D. 利用问题句中的特征词(Nicholas A. Christakis)作为答案线索， 同时利用备选项B中的典型细节信息结构(eating habits)作为答案线索， 在文章中查找答案相关句：

　　Obesity can spread from person to person, much like a virus, researchers are reporting today. When one person gains weight, close friends tend to gain weight, too.

　　Their study, published in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003.

　　The investigators knew who was friends with whom as well as who was a spouse or sibling or neighbor, and they knew how much each person weighed at various times over three decades. That let them reconstruct what happened over the years as individuals became obese. Did their friends also become obese? Did family members? Or neighbors?

　　The answer, the researchers report, was that people were most likely to become obese when a friend became obese. That increased a persons chances or becoming obese by 57 percent. There was no effect when a neighbor gained or lost weight，however, and family members had less influence than friends.

　　(第2题答案相关句)(第5段)It did not even matter if the friend was hundreds of miles away, the influence remained. And the greatest influence of all was between close mutual friends. There, if one became obese, the other had a 171 percent increased chance of becoming obese, too.

　　(第6段)The same effect seemed to occur for weight loss, the investigators say. But since most people were gaining, not losing, over the 32 years, the result was, on average, that people grew fatter.

　　(第7段)Dr. Nicholas A. Christakis, a physician(医生) and(兼) professor (教授)of medical(医学的) sociology(社会学) at Harvard Medical School(哈佛医学院)and a principal(主要的， 校长， 负责人) investigator(调查人) in the new study(研究), said one explanation (问题句中的核心词)was that friends affected(影响) each others(彼此)’ perception(理解)(perception是feeling的近义词) of fatness(肥胖). When a close friend (亲密的朋友)becomes obese, obesity may not look so bad.

　　答案相关句(第七段第一句)涉及到了Dr. Nicholas A. Christakia对于这种现象的解释：朋友之间对于肥胖的感知是互相影响的。因此D是答案。