题目

一名足球守门员练习折返跑，从球门线出发，向前记作正数，返回记作负数，他的记录如下：（单位：米）+5，-3，+10，-8，-6，+12，-10（1）守门员最后是否回到了球门线的位置？（2）在练习过程中，守门员离开球门最远距离是多少米？（3）守门员全部练习结束后，他共跑了多少米？ 答案：【答案】（1）回到了球门线的位置（2 ）12米（3）58米【解析】试题分析：（1）将各数进行相加，看结果是否为零，如果结果为零就说明回到了球门线的位置；（2）根据有理数的加法计算法则求出每次离球门线的距离，然后进行比较大小；（3）将各数的绝对值进行相加，得出答案．试题解析：⑴、（+5New research suggests that cutting daily sitting time to less than three hours might extend your life by two years.    “Humans were designed to move. But modern lifestyles and office jobs rarely encourage us to walk around,” says Peter Katzmarzyk, an expert at the University of Louisiana.    “Sitting is common in our lives today. We sit while we’re driving, eating and watching TV. And many of us sit for many hours at work.” Katzmarzyk said.    “We can’t throw away physical activity. It’s extremely important. We have 60 years of researchers showing us that.” Katzmarzyk said.    Katzmarzyk and other researchers are trying to discover how sitting all day affext our lifespans（寿命）.    “This is a relatively new area of study…Studies that have assessed the relationship between sitting and death or television viewing and death have been very rare in the last four or five years,” said Katzmarzyk.    Katzmarzyk and his colleagues analyzed data from these studies, which involved almost 167,000 adults. Then they turned to a government-run survey of Americans to find out exactly how much time people spend sitting and watching.    Not only did the team find that U.S. citizens could live longer by sitting less, they found that cutting TV time to less than two hours a day could add an extra 1.4 years to their lives. People who’ve spent half their waking lives sitting down might well ask, “Is it ever too late to make a change?” “We would say ‘No. It’s never too late.’ Physical activity is good for you at every age.” Katzmarzyk said. Katzmarzyk says studying this problem has inspired his team to make a few changes in their own lives. They recommend a few simple changes: frequently getting up from your desk, taking walks at lunch time, and instead of e-mailing colleagues, walking over to their offices and talking face-to-face——all activities that can be enjoyable as well as life-extending. 1.Peter Katzmarzyk seems to believe that _____. A. we should not sit for a long time    B. most people like to sit most of the time C. office jobs encourage us to walk a lot   D. modern lifestyles are good for our health 2.The underlined word “that” in paragraph 4 probably refers to _____. A. taking physical exercise is important   B. many researches should be carried out C. we should exercise during working hours D. people should focus on their health at work 3.Why did Katzmarzyk and his colleagues turn to a government-run survey? A. To collect information for the government B. To know how long people sit and watch TV C. To find what citizens do in their spare time’ D. To discover how sitting for long affects their lives 4.The best title of the text would be _____. A. What Is the Healthiest Lifestyle？ B. Sitting for a Long Time Is Bad for Us C. Study Suggests Sitting Less Can Extend Life D. It Is Never Too Late to Change Our Way of Life