EResearchers have just offered evidence in a study that says obesity appears to spread thr

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Researchers have just offered evidence in a study that says obesity appears to spread through social ties, much like a virus. When one person gains weight, their close friends often follow, but the finding might also offer hope.
If friends help make obesity acceptable, then might also be influential in losing the fat. The researchers note that support groups are already an effective tool in dealing with other socially influenced problems, like alcoholism.
The findings appeared in the New England Journal of Medicine, The researchers used information collected from 12,000 people. It was collected between 1971 and 2003 as part of the Framingham Heart Study.
The information was highly detailed. There was even contact information for close friends of the people in the study.
The researchers examined more than 40,000 social ties. They found that a person’s chances of being severely overweight increased by 57% if a friend had bee obese.
Nicholas Christakis of Harvard Medical School was a lead investigator in the study. He says there is a direct causal relationship between a person getting fat and being followed in weight gain by a friend.
The study found that the sex of the friends was also an influence. In same-sex friendships, a person had a 70% increased risk of being obese. Men had a 44% increased risk of being obese after weight gain in brothers. In sisters, it was 67%. Between husbands and wives, it was a little less than 40%.
The researchers also considered the effect of where people lived in relation to each other. James Fowler of the University of California, San Diego, was the other lead investigator. He says a friend who lives a few hundred kilometers away has as much influence as one in the same neighborhood. He says the study demonstrates the need to consider that a major part of people’s health is tied to their social connections.
Both investigators say their research shows that obesity is not just a private medical issue, but a public health problem.
67. What does the underlined sentence in Para2.mean?
A. Obesity has a negative influence on a close friend.
B. Friends might also play a part in losing weight.
C. One might have a positive influence on one’s friend.
D. Friends usually don’t follow each other to lose weight.
68. Who is mostly likely to gain weight?
A. A man who has a fat brother.     
B. A husband who has a fat wife.
C. A wife who has a fat husband. 
D. A woman who a fat female friend.
69. Which of the following statements doesn’t the passage agree with?
A. You are sure to lose weight if you have a skinny friend.
B. If one gains weight, one’s friends are likely to get fat.
C. A person’s health is closely linked with his /her social relationship.
D. Even if the friend lives far away, the influence still remains.
70. The reason why the study involves both family members and friends is that     .
A. researchers fail to find a more different sample
B. researchers have different ideas for family members and friends
C. researchers can meet these people regularly
D. researchers can pare the results67—70  BDAD