17．PALO AITO，California-"Switching off the television may help prevent children from getting fatter-even if they do not change their diet or increase the amount they exercise，"US researchers said last week．
A study of 192third and fourth grades，generally aged eight and nine，found that children who cut the number of hours spent watching television gained nearly two pounds（0.91kg） less over a one-year period than those who did not change their television diet．
"The findings are important because they show that weight loss can only be the result of a reduction in television viewing and not any other activity，"said Thomas Robinson，a pediatrician（儿科专家） at Stanford University．
"American children spend an average of more than four hours per day watching television and videos or playing games，and rates of childhood being very fat have doubled over the past 20years，"Robinson said．
In the study，presented this week to the Pediatric Academic Societies'annual meeting in San Francisco，the researchers persuaded about 100of the students to reduce their television viewing by one-quarter to one-third．
Children watching fewer hours of television showed a significantly smaller increase in waist size and had less body fat than other students who continue their normal television viewing，even though neither group ate a special diet nor took part in any extra exercise．
"One explanation for the weight loss could be the children unstuck to the television may simply have been moving around and burning off calories，"Robinson said．
"Another reason might be due to eating fewer meals in front of the television．Some studies have suggested that eating in front of the TV encourages people to eat more，"Robinson added．
51．The purpose of the first two paragraphs isD．
A．to report the time children spend watching TV
B．to show that more TV time leads to getting fatter
C．to tell us the best way to reduce weight
D．to introduce the background of the research
52．According to the passage，the time American children usually spend on watching TVA．
A．is more than four hours a day
B．is less than four hours a day
C．doubled in the last twenty years
D．is more than on any other activities
53．The time the 100children spend on TV every day is aboutC in the study．
A．a quarter of an hour
B．four hours
C．three hours
D．one hour
54．Which of the following statements is TRUE according to the passage？B
A．Weight increase owes to the result of a reduction in TV viewing．
B．The percentage of children getting fatter has doubled in the last 20years．
C．Children usually eat less while watching TV．
D．Children usually eat nothing while watching TV．
55．The main idea of the passage would beA．
A．less TV time helps reduce children's weight
B．fewer meals is a must in reducing children's weight
C．the less you eat，the thinner you will be
D．more exercise is of great benefit to reduce weight．
分析 文章是关于看电视和肥胖的关系，美国儿童看电视时间太长，文章建议减少孩子看电视的时间，并分析原因．
解答 51．D．推理判断题．根据第二段第二行children who cut the number of hours spent watching television gained nearly two pounds（0.9kg） less．可知前两段的目的是为了介绍本研究的背景；故选D．
52．A．细节理解题．根据第四段第一行American children spend an average of more than four hours per day watching television and videos or playing video games可知美国孩子通常花在看电视上的时间超过四小时；故选A．
53．C．推断题．根据倒数第四段最后一句reduce their television viewing by one-quarter to one-third可知孩子们花在每天看电视的时间大约是三小时；故选C．
54．B．细节理解题．根据第四段and rates of childhood being very fat have doubled over the past 20years可知儿童越来越胖的比例已近20年中翻了一番；故选B．
55．A．主旨大意题．通读全文，文章主要讲了看电视和肥胖的关系，美国儿童看电视时间太长，文章建议减少孩子看电视的时间，故选A．
点评 考察学生的细节理解和推理判断能力，做细节理解题时一定要找到文章中的原句，和题干进行比较，再做出正确的选择．在做推理判断题不要以个人的主观想象代替文章的事实，要根据文章事实进行合乎逻辑的推理判断．
