2009年6月英语四级模拟题和答案下载(五)

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　　Part ⅡReading Comprehension(Skimming and Scanning) (15 minutes)
　　Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1.
　　For questions 1－7, mark
　　Y (for YES)if the statement agrees with information given in the passage;
　　N (for NO)if the statement contradicts the information given in the passage;
　　NG(for NOT GIVEN)if the information is not given in the passage.
　　For questions 8－10, complete the sentences with the information given in the passage.
　　Obesity in Children
　　Obesity in children and adolescents is rising at an alarming rate. Currently over 15% of young people over 6 years old are obese, and obesity is also increasing among children aged 5 and younger.
　　Children are considered to be overweight if the BMI (Body Mass Index) is over 85% of the weight group in their age and sex categories. If it is 95% and over, they are considered to be obese. Adolescents are generally judged according to adult criteria for obesity, although there are other considerations in this population. Ethnic variations, timing of growth spurts, and higher normal fat levels around puberty can cause disparities in these measurements.
　　Causes and Risk Factors for Obesity in Children
　　Lifestyle Factors. Without educational or parental guidance, children are extremely vulnerable to the intense cultural pressures that are largely responsible for the obesity epidemic. Neither the media nor the educational system has strong well-financed programs that encourage healthy-alternatives, including exercise and healthy foods. The following are some specific problems created by the culture:
　　* Excessive television watching plays a critical role in obesity in children. Not only is it a sedentary activity, but television also offers innumerable temptations with its advertisements for fast foods, sugar cereals, and unhealthy snacks. In one study obesity rates were lowest in children who watched television one hour or less a day and highest in those who watched four or more hours.
　　* Sugar, particularly from soda, other sweetened beverages, and fruit juice, may be major contributors to childhood obesity. One study reported that drinking soda regularly increases a child's risk for obesity by 60%.
　　* Less physical exercise and greater sedentary activities play another significant role in obesity in children. A high level of physical, activity-not just using up energy-is important for weight control in young people.
　　Family History. Parental obesity more than doubles the risk that a young child, whether thin or overweight, will become obese as an adult. In older children and teenagers, obesity in parents starts to count less as a predictor for body weight than their own weight. The risk may be due to environmental or genetic factors, or both.
　　Ethnic and Socioeconomic Factors. As in adult populations, children from lower socioeconomic groups and minority populations are at higher risk for obesity. For example, among young Mexican Americans and African Americans, there has been an increase in overweight prevalence of about 13% to over 23%.
　　Factors Surrounding Birth. The following factors surrounding birth are associated with a child's weight:
　　* Low birth weight is a risk factor for later obesity and diabetes. One theory is that humans have a "thrifty gene" that produces metabolic changes in infants with low birth weight. Such changes affect insulin and fat accumulation in order to produce a "catch-up" weight in these young children as quickly as possible. This rapid weight gain in infancy increases the gain risk for obesity in children and also in young adulthood.
　　* In a study of African American children, having an overweight pregnant mother increased the risk for later weight gain, but low birth weight did not.
　　Although some small studies have reported protection against obesity from breastfeeding, evidence is weak. In a 2003 study, for example, children who were breast fed for three to five months had a lower risk for obesity, but prolonged breastfeeding had no effect. Nevertheless, given the healthful effects of breast feeding and the possibility that it may have even a slight impact on childhood obesity, it is highly recommended.