2011年12月英语四级全真预测试卷及答案(2)

　　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.
　　Health Consequences of Childhood Obesity
　　Children and adolescents who are obese have poorer health than other children. Studies are reporting unhealthy cholesterol levels and high blood pressure in obese children and adolescents. Of great concern is the dramatic increase in type 2 diabetes in young people, which is most certainly largely due to the increase in obesity. Obesity in children is also linked to asthma, gallbladder problems, sleep apnea, and liver abnormalities. Childhood obesity may be partly responsible for the declining age for onset of puberty in girls, with subsequent risks for breast cancer.
　　It is not clear yet how many of these childhood problems persist in people who achieve normal weight as adults. Staying overweight into adulthood certainly confers health risks.
　　Managing Overweight and Obese Children
　　Childhood obesity is best treated by a non-drug, multidisciplinary approach including diet, behavior modification, and exercise. Some evidence suggests that reducing calories by only 200 to 260 per day would prevent weight gain in most overweight children. Here some tips for children who are overweight:
　　* Limit or avoid if possible take-out, fast foods, high-sugar snacks, commercial packaged snacks, soda and sugar sweetened beverages (including too much juice).
　　* Let children snack but make sure the snacks are healthy. Eating small frequent healthy meals (instead of two or three large ones) has been associated with being thinner and having a better cholesterol profile.
　　* Let children choose their own food portions. One study indicated that children naturally ate 25% less than they chose their own portion size. When they were given larger portions their bite sizes were larger and they ate more.
　　* Don’t criticize a child for being overweight. It does not help and such attitudes could put children at risk for eating disorders, which are equal or even greater dangers to health.
　　* Limit television, video games, and computer use to a few hours a week. This can contribute significantly to weight control, regardless of diet and physical activity.
　　* For young children, try the traffic-light diet. Food is designated with stoplight colors depending on their high caloric content: Green for go (low calories); yellow for “eat with caution” (medium calories); red for “stop” (high calories).
　　* Try a low-glycemic index diet. This may be as beneficial and possibly more than a standard reduced-fat diet in obese children. Such a diet focuses on carbohydrates, such as dried beans and soy, that raise blood sugar more slowly than others. This diet is sometimes used in diabetes and as a dietary approach in overweight adults.
　　1. Overweight children are those whose BMI is over 85% of the weight group in their age and sex categories.
　　2. The educational system is positive in promoting exercise and healthy foods, according to the passage.
　　3. It is observed that children watching television one hour or less a day tend to be less likely to suffer from obesity.
　　4. The intake of sugar among children is an important contributor to childhood obesity.
　　5. In most cases, obese children tend to have parents suffering obesity, as environmental or genetic factors are the major reasons for childhood obesity.
　　6. Infants with low birth weight may face a risk for obesity as they grow up into childhood and young adulthood.
　　7. For obese children, achieving a healthy weight becomes more difficult as they get older, as the persistence is biological.
　　8. Obese children and adolescents have poorer health, as they are reported to have unhealthy .
　　9. It is suggested that reducing calories would prevent weight gain in most overweight children.
　　10. The author believes that it does not help to criticize children for being overweight, as this may increase the risk for .