1 . Running is often tiring and a lot of hard work, but nothing beats the feeling you get after finishing a long workout around the track.

But while it’s long been believed that endorphins (内啡肽) —chemicals in the body that cause happiness—are behind the so-called “runner’s high”, a study suggested that there may be more to this phenomenon than we previously knew.

According to a recent study published by a group of scientists from several German universities, a group of chemicals called endocannabinoids (内源性大麻素) may actually be responsible for this familiar great feeling.

To test this theory, the scientists turned to mice. Both mice and humans release high levels of endorphins and endocannabinoids after exercise. After exercising on running wheels, the mice seemed happy and relaxed and displayed no signs of anxiety. But after being given a drug to block their endorphins, the mice’s behavior didn’t seem to change. However, when their endocannabinoids were blocked with a different drug, their runners’ high symptoms seemed to fade.

“The long-held notion of endorphins being responsible for the runner’s high is false. Endorphins are effective pain relievers, but only when it comes to the pain in your body and muscles you feel after working out,” Patrick Lucas Austin wrote on science blog Lifchacker.

Similar studies are yet to be carried out on humans, but it’s already known that exercise is a highly effective way to get rid of stress or anxiety. The UK’s National Health Service even prescribes (开药 方) exercise to patients who are suffering from depression. “Being depressed can leave you feeling low in energy, which might put you off being more active. Regular exercise can improve your mood if you have depression, and its especially useful for people with mild to moderate (中等的) depression,” it wrote on its website.

It seems like nothing can beat that feeling we get after a good workout, even if we don’t fully understand where it comes from. At least if we’re feeling down, we know that all we have to do is to put on our running shoes.

2 . When I tried out for the football team during the summer before 9th grade, I never imagined how important this sport would become in my life. Football is a _____ sport, at times almost painful, and practices really _____ a team’s physical and mental limits. Without trust in my own ability and a strong sense of commitment, I would never have managed to continue after years of hard work as a player, and with countless _____.

In the first year, I played on the defensive line. This was an amazing _____ that gave me a great sense of achievement. But in the last game of the season, I was seriously injured. I was prohibited from any physical activities for six months. After going _____ a series of physical treatments, I returned to the field as a team captain. I practiced harder than ever to make up for my _____ time.

In September, during my junior year, my name was mentioned in the local newspaper as the key defensive lineman on the team. After playing a fantastic season, I was given the _____ of the Most Valuable Player.

_____, my skills in football do not magically extend to other sports. During the winter break, I went on a snowboarding trip and seriously injured my right shoulder. I had to have four _____. Since I could not use my right arm for two months, I had to learn how to write and eat using my left hand.

______ life must go on. I knew that my own present efforts would decide my future, so I ______ the strict training program to build up strength and improve flexibility in my ______. After an eight-month recovery, I was back to the field playing football, the sport I ______.

In this sense, the world of football has taught me an important life lesson: ______ and commitment make what seems impossible ______. This lesson from football is the one that can be applied to every part of life.

According to a study published in the UK recently, those     1     like jogging and do this kind of exercise     2    (regular) for at least one hour a week have very high chances to live a longer life. The study’s Danish researchers     3    (convince) that choosing this kind of physical activity can bring us a priceless reward, which is 5 to 6 more years of life! Moreover, to achieve better results, the researchers suggest     4    (limit) yourself to gentle jogging rather than fast-pace and     5    (tire) distance running. The scientists found that jogging     6    (benefit) are maximized when done at an average or even slow-pace exercising, and just one or two hours of jogging a week can be enough for you to achieve success, regardless of your age or health condition.

The scientists analyzed     7     data on about 20,000 people     8    (age) between 20 and 93, collected for over 35 years by the Copenhagen City Heart Study. According to Dr. Peter Schnohr, the leader researcher, it was found that jogging is relevant     9     as much as a 44 percent     10    (low) risk of death. The life expectancy increase in men is as much as 6.2 years, and for women it is as much as 5.6 years.

Sports Day was getting close in the school. All the children were very excited and were practicing for the big race. John, one of the fast runners of the school, was confident that he would win for he was not doing anything at all. “You have to work hard to come first in the race John. You are not practicing at all,” said John’s mother.

“Mom, you know how fast I am! Why should I waste my time running? Only I will win; no one else will win!”said John. “John, you may be right but talent (天赋) without hard work is not good at all. This laziness of yours will cost you greatly,” his mother warned him. John just laughed. He was so confident that he would win the trophy (奖杯) as no one else in his class was as fast as he was!.

Tim, a classmate of John, was also participating (参加) in the running race. He was not a fast runner. However, he practiced till late at night and had developed great endurance (持久力) to run the race.

There were a few days left for the Sports Day but John did not practice at all. On the other hand, Tim practiced day and night.

The Sports Day was almost around the corner but John was confident that no one could beat him and had not practiced at all. But Tim with his hard work had become a very great runner.

At last, the Sports Day arrived. All the students showed up on the ground to cheer their favorites. The coach blew the whistle (口哨) and everyone began to run toward the finishing line. It was so exciting. John and Tim left all the racers far behind. Both of them were neck to neck.

Suddenly, John went ahead of Tim.

John’s mother came up to Tim and praised him for his hard work.

An Unforgettable Sports Meet

9 . Teenagers’ fitness is now a major concern, to which physical exercise is very important. It reduces stress and improves fitness. Exercise makes your body strong, and helps you to keep the right body weight. Sports scientist Dr.Helen Lopez offers the following advice to teenagers: “Firstly, you need to find out your present level of fitness. Then you can design a programme that will help you become healthier.”

Dr Lopez suggests that there are three levels of fitness that need a change of lifestyle. “Overweight” means that the person gets very little exercise and often has a serious weight problem. “Inactive” means that the person does not join in many physical activities, but is not seriously overweight. “Active” refers to people who take part in sports and other physical activities, but do not have a high fitness level.

According to Dr Lopez, overweight teenagers should keep active to keep healthy. Ride a bike, play volleyball or basketball for a while, and go for a twenty-minute walk each day. All these will help to burn up calories. Inactive teenagers should do similar activities, but add some bending and stretching exercises, such as push-ups and sit-ups, starting with twenty of each a day. “Inactive people can take a little more exercise than overweight people because their bodies are stronger,” said Dr Lopez. The same principle applies to active teenagers.

Dr Lopez suggests one hour a week or more on running and other forms of intensive exercise, together with fifteen minutes a day spent on stretching and bending activities. “These are really important in order to prevent injuries,” Dr Lopez said. Some weight-training and other body-strengthening exercises could also be planned in the programme in order to increase the personˈs strength.

Yours sincerely,

Li Hua