There are some injuries that are common to all types of extreme sports. The following are some of the important things to do to prevent extreme sports injuries. {#blank#}1{#/blank#} But they can definitely minimize the risk of injuries.

    Warm up.

    {#blank#}2{#/blank#} They include a combination of cardiovascular(心脏血管的)exercises, strength drills and stretching. Cardiovascular exercises increase body temperature, heart rate and blood circulation, which is required for further movement of the body. Strength drills increase the stamina of the body, while stretching warms up the muscles preparing them for sudden forceful movements. {#blank#}3{#/blank#} It also plays an important role in boosting the team spirit for a team sport. A warm-up session should last for at least 20 minutes and it can extend up to half an hour.

    Avoid overworking.

    There are some people who do not exercise their body for the sport on a regular basis and perform a week's task in a day or two. {#blank#}4{#/blank#} They do not realize the effect of overworking during the performance and keep doing it until they feel extremely tired. Apart from the actual sport, one should also avoid overdoing the warm-up exercises before the activity.

    {#blank#}5{#/blank#}

    Just as warming up is essential before any rigorous(充满活力的) physical activity, cooling down the body after playing a rigorous sport is also a significant part of physical conditioning. When you are done with your sports session, you can conclude with some walking, jogging or light running. Slight stretching exercises, focusing on specific muscles, will also be useful for cooling down the body.

A. Cool yourself down.

B. Look for a coach to train you.

C. These people are likely to suffer from extreme sport injuries.

D. However, there are no perfect methods which can assure you 100% safety.

E. Along with physical preparation, warming up prepares you mentally to begin a sport.

F. You should also be careful about your clothing selection for warmth and protection.

G. Warm-up exercises are very important before you begin any sports practice.

    Walt Disney is credited for creating such wonderful things as Donald Duck and Mickey Mouse. However, he cannot take the credit for creating other well-loved characters, such as Cinderella and Snow White. They are almost automatically associated with Disney because Disney turned old fables(寓言) into cartoon movies.

    The original Cinderella varies very much from the Disney version we know today. It started off with the girl mourning her mother's death and going to her tomb three times a day. In addition, there were only birds that helped Cinderella; there was no such thing as a fairy godmother or helpful mice, nor was there mention of a horse and carriage.

    The stepsisters were cruel: they always threw Cinderella's food into the ashes of the fire and made her sleep on the ashes on the floor, hence（因此）her name.

    In the original story, the king's ball actually lasted for three days. With the help of the birds, the girl, beautifully dressed, danced with the prince on all three nights and the prince fell in love with her. However, she broke away from him to rush back home each night. On the last night, the prince placed soothing sticky on the stairs; as Cinderella made her escape, a shoe got stuck on it.

    Here now is where the story becomes unpleasant: when the prince went to the house looking for the girl whose foot fit the shoe, the wicked(邪恶的) stepmother told one of her two daughters to cut off her big toe to fit into the shoe. The daughter did as told. So the prince took her away to be his bride. But when they passed the tomb of Cinderella's mother, the birds called out to the prince,

    “Turn and peep, there's blood in the shoe;the shoe is too small, the true bride waits for you.”

    Realizing he had been tricked, the prince returned the daughter to her mother. The other then had to cut off part of her heel in order to fit into the shoe, with the same result. Only Cinderella's foot fit perfectly and so the prince chose to marry her. The story ends with the wedding day: as Cinderella's two stepsisters followed her, pretending to be devoted to her so that they could enjoy the king's riches, two birds flew by and plucked(啄) out their eyes. Because of their wickedness and falsehood, they had to spend the rest of their days blind.

    The original Cinderella is so different from the Disney version. Thank goodness Disney made such changes; it indeed was a wise move.

    In America, parents tend to encourage their children to develop their potential (潜能) to the fullest extent. Fathers and mothers frequently teach their children both ambition and the confidence necessary to work toward their goals. American parents are always active in concentrating on what their kids can do, not what they can't. As a result, millions of American boys and girls grow up hoping to become actors and athletes, diplomats and doctors. Many of them even want to become president.

    American parents often encourage their children to become involved in extra activities of all types at school, such as student government, sports and music. They believe that only through taking part in these activities can their children become mature young adults.

As we all know, school work is important. But parents should realize that the social skills their children learn from natural conversations with each other are as important as schoolwork and the skills they will need in the future work. What's more important in their work is that their children should have a sound knowledge of physics or the ability to communicate effectively.

As a rule, Chinese parents don't educate their children about the same kind of ambition and confidence as Americans do, nor do they encourage the same level of participation in extra activities. Children are typically advised to study hard and pass exams. They have to spend a lot of time in doing much schoolwork every day. It is a great waste of time to do so.

Now more and more Chinese parents have recognized that they should pay attention to developing the potential of their children. I hope that leaders in Chinese educational circles should take some measures to develop the potential of their children. I am very confident about it.

    Pigeons may only have a brain the size of a thimble (顶针), but it appears that pigeons can categorize and name objects in the same way human children learn new words.

    A new study from the University of Iowa has shown that the birds are capable of learning to categorize 128 different photographs into 16 basic categories.

    Scientists taught three pigeons to sort out different kinds of dogs or types of shoes, for example by using a particular symbol in exchange for a reward. When they were shown black and white pictures of previously unseen dogs or shoes, the birds were able to correctly match these with the corresponding symbols.

    The scientists behind the project say this is a similar approach taken by young children when they are first learning words for objects. However, the researchers said it took their birds around 40 days to perfect the task of learning just 16 categories.

    Professor Edward Wasserman, who led the work, said: "Our birds' rate of learning appears to have been quite slow. Would children learn faster than pigeons? Almost certainly. However, our pigeons came to the experiment with no background knowledge at all. Thus, the more relevant comparison group may be newborn babies, who indeed take 6–9 months to learn their first words."

    Writing in the journal Cognition, the researchers said their experiment was a very simple mirror of the way children are taught words — by their parents pointing to pictures and asking them to name the object.

    Pigeons are known to be smarter than many birds. Professor Bob McMurray, who also took part in the study, said the results showed that human learning is not as unique as was previously believed.

    He said: "Children are facing a huge task of learning thousands of words without a lot of background knowledge to go on. For a long time, people thought that such learning is special to humans. What this research shows is that the ways in which children solve this huge problem may be shared with many species.

    People typically wash their hands seven times a day in the United States, but they do it at a far higher temperature than is necessary to kill germs, a new study says. The energy waste is equivalent to the fuel use of a small country. Amanda R. Carrico, a research assistant professor at the Vanderbilt Institute for Energy and Environment in Tennessee, told National Geographic that hand washing is often “a case where people act in ways that they think are in their best interest, but they in fact have inaccurate beliefs or outdated perceptions.”

    Carrico said, “It's certainly true that heat kills bacteria, but if you were going to use hot water to kill them it would have to be a way too hot for you to tolerate.”

Carrico said that after a review of the scientific literature, her team found “no evidence that using hot water that a person could stand would have any benefit in killing bacteria.” Even water as cold as 40°F (4.4℃) appeared to reduce bacteria as well as hotter water, if hands were scrubbed, rinsed(冲洗)and dried properly.

    Using hot water to wash hands is therefore unnecessary, as well as wasteful, Carrico said, particularly when it comes to the environment. According to her research, people use warm or hot water 64 percent of the time when they wash their hands. Using that number, Carrico's team calculated a significant impact on the planet.

    “Although the choice of water temperature during a single hand wash may appear unimportant, when multiplied by the nearly 800 billion hand washes performed by Americans each year, this practice results in more than 6 million metric tons of CO2 equivalent emissions annually,” she said.

    The researchers published their results in the July 2013 issue of International Journal of Consumer Studies. They recommended washing with water that is at a “comfortable” temperature, which they noted may be warmer in cold months and cooler in hot ones.

    A scientist once said: "I have concluded that the earth is being visited by intelligently controlled vehicles from outer space."

    If we take this as a reasonable explanation for UFOs (unidentified flying objects), questions immediately come up.

    "Why don't they get in touch with us, then? Why don't they land right on the White House lawn and declare themselves?" people asked.

In reply, scientists say that, while this may be what we want, it may not necessarily be what they want.

    "The most likely explanation, it seems to me," said Dr. Mead, "is that they are simply watching what we are up to—that responsible society outside our solar system is keeping an eye on us to see that we don't cause a chain reaction that might have unexpected effects for the outside of our solar system."

    Opinions from other scientists might go like this: "Why should they want to get in touch with us? We may feel we're more important than we really are! They may want to observe us only and not interfere(干涉) with the development of our civilization. They may not care if we see them but they also may not care to say 'hello'."

    Some scientists have also suggested that Earth is a kind of zoo or wildlife reserve. Just as we set aside wilderness areas and wildlife reserves to allow animals and growing things to develop naturally while we observe them. So perhaps Earth was set aside ages ago for the same purpose.

    Are we being observed by intelligent beings from other civilizations in the universe? Are they watching our progress in space travel? Do we live in a huge "zoo" observed by our "keepers," but having no communication with them?

    Never before in our history have we had to face ideas bravely like these. The simple fact is that we, who have always regarded ourselves as supreme in the universe, may not be so. Now we have to recognize that, among the stars in the heavens, there may very well be worlds lived by beings who are to us as we are to ants.