写作：GRE作文ARGUMENT126篇真题五六

５６、Typically, as people age, their bone mass decreases, making them more vulnerable to bone fractures. A recent study concludes that the most effective way to reduce the risk of fractures in later life is to take twice the recommended dose of vitamin D and calcium¹ daily. The three-year study followed a group of French women in their eighties who were nursing-home residents. The women were given daily supplements of twice the recommended dose of vitamin D and calcium. In addition, the women participated in a light weightlifting program. After three years, these women showed a much lower rate of hip² fractures than is average for their age.