题目

When one person gains weight, their close friends often follow. Researchers have just offered evidence in a study that says obesity（肥胖）appears to spread through society. But the findings might also offer hope.     If friends help make obesity acceptable, then they 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(酗酒).The findings appeared in the New England Journal of Medicine. The researchers used information collected from 12,000 people. It w下列表示物质组成、结构的化学用语正确的是（　　）A．氮分子的结构式：N≡NB．Cl-的结构示意图：C．NaCl的电子式：D．8个中子的碳原子的符号：12C