In the past decade the popularity of rock climbing has greatly increased, and so has the number of injuries. It has been estimated that rock climbing is now enjoyed by more than 9 million people in the US each year. Study findings revealed a 65 percent increase in the number of patients that were treated in US emergency departments for rock climbingrelated injuries between 1991 and 2008. The study, published in the online issue of the American Journal of Preventive Medicine, found that about 40, 000 patients were treated in US emergency departments for rock climbingrelated injuries between 1991 and 2008. The most common types of rock climbingrelated injuries were fractures (骨折) and sprains (扭伤). The ankle was the most common body part to be injured (40 percent). Climbers in the study ranged in age from 2 to 74, with an average age of 26. The study also found that women took up a quarter of the injuries. Falls were the primary reason for injury with over threequarters of the injuri es occurring as the result of a fall. The severity of fallrelated injuries had a lot to do with the height of the fall. Patients who were injured after falling from a height over 20 feet were 10 times more likely to be treated than patients who were injured falling from 20 feet or lower. 'We found that the climbers who fell from heights higher than 20 feet took up 70 percent of the patients treated for a rock climbingrelate d injury,'  explained the study author Lara McKenzie, PhD, director at the Center for Injury Research and Policy at Nationwide Hospital.' This trend, combined with the fact that rock climbers have a higher hospitalization rate than other sports and recreational injuries, demonstrates the need to increase injury prevention efforts for climbers.' 1. Which body part is most likely to get injured for a climber? A. The arm. B. The ankle. C. The knee. D. The hand. 2. How many women climbers in America got injured while climbing a rock between 1991 and 2008? A. About 40,000. B. About 30,000. C. About 20,000. D. About 10,000. 3. The s everity of climbers' fallrelated injures is mainly related to ________. A. the height of the fall B. the climber's age C. the climber's health conditions D. the climber's climbing experience 4. The underlined word 'demonstrates' in the last paragraph can be replaced by '________'. A. demands B. prevents C. proves D. describes 5. The purpose of the passage is to ________. A. show that rock climbingrelated injuries have increased B. tell readers rock climbing is an adventurous sport C. warn readers of the danger of rock climbing D. call on doctors to increase injury prevention efforts