题目

A New Mind-set With teenagers at home, tempting foods were always around Mary Saltsman. But she made one change a week and the weight started to come off --- 18 pounds so far. And she’s thrilled about another positive benefit: Her kids have started imitating her healthy eating habits. A New Way of life Debra Outlaw’s ChangeOne journey began 116 pounds ago. Now, she is much healthier and more in control of her eating. “Staying with the plan consistently is key,” she says. “With dedication and perseverance, every temptation does not become a war. Conquering Snacks Snacking wa如图，线段AB是⊙O的直径，弦CD丄AB，∠CAB=20°，则∠BOD等于（　　）A. 20° B. 30° C. 40° D. 60° C 【解析】试题分析：由线段AB是⊙O的直径，弦CD丄AB，根据垂径定理的即可求得： ，然后由圆周角定理可得∠BOD=2∠CAB=2×20°=40°． 故选：C．