You're happy to let your best friend borrow your mountain bike, but would you be willing to loan it out to a total stranger if you could make some money from the arrangement?

    That's the idea behind peer-to-peer (P2P) renting, a new model concluded by sites such as eBay and Craigslist. Instead of selling an idle (闲置) thing, you loan it to people in your town, get paid a small rental fee and gel it back when the borrower's done with it. In the past few years, almost a dozen websites have popped up promising to connect lenders and borrowers. For example, you can use GetAround to rent out your car or motorcycle, SnapGoods to rent out electronics and gadgets, ToolSpinner to rent electric drills and lawnmowers, Zaarly and Knb to rent out a little bit of everything else.

    Old as it may sound, P2P renting is more high-tech than before, with websites that avoid cash for credit cards. A user creates an online listing for the item she wants to rent out, choosing her own rental fee. When someone wants the item, he keeps it on an online calendar, and the two arrange a time and place for pickup. Each site operates a little differently, but all use technology to make renting easy, safe and relatively inexpensive.

    Why rent your idle things? You may not make a ton of money, but it is a good way to get some use out of idle things. The people who rent those goods are able to save thousands of dollars by renting instead of buying new.

    There may be other benefits. "It brings convenience, security and adventure," says Ali Hart, JustSharclt's spokesperson. “But, more importantly, we're really connecting people and building community, too."

    Get to know your neighbors and make a few dollars in the process? Sounds like a good deal.

    A good teacher is many things to many people. In my own experience, the people I respect the most and think about the most are the teachers who demanded the most discipline (纪律) from their students.

    I miss one teacher in particular that I had in high school. I think she was a good teacher because she was a very strict person. I remember very clearly a sign on her classroom door. It was a simple sign that said,    "Laboratory: in this room the first five letters of the word was stressed not the last seven." In other words, labor for her was more important than oratory, which means making speeches.

    She prepared her work very carefully and told us to do the same. We got lots of homework from her. Once she had broken her arm, and everybody in the class thought that maybe the homework load would be reduced, but it continued just the same. She checked our work by stamping her name at the bottom of the papers to show that she had read them.

    I think sometimes teachers who demand the most are liked the least. But as time goes by, this discipline really seems to benefit the students.

    When was the last time you relied on an old-fashioned map to figure out the route to an unfamiliar place? For many, the GPS has revolutionized navigation, making a paper map almost obsolete? So how has this piece of technology developed over its 26 years of existence? On February 14,1989,the first satellite in the US Global Positioning System was sent into space from Cape Canaveral, beginning the start of one of the wonders of the modern world.

    GPS stands for Global Positioning System, which is made of a network of around 30 satellites that move around the earth. The system uses a process called trilateration to find out one's position. By measuring the time it takes for the signal to reach one satellite, the GPS can determine your distance from the satellite, creating a sphere(范围) of possible locations. Measuring your distance from at least three satellites will narrow your location to the place where the three spheres cross one another, to the accuracy(精确) of about less than 1 meter!

    The GPS was first invented during the Cold War by the United States Department of Defense. In 1960, the first system, which was made of just five satellites, was put into place. It was initially created for strictly military(军事的) use; however, in 1983, as a result of faulty navigation technology, a Korean passenger plane mistakenly flew into USSR territory(苏联领土) and was shot down. In order to prevent such bad events, American President Ronald Reagan allowed civilian(民用的) use of the GPS.

    Over the next ten years, the system's accuracy improved as the network was increased to 24 satellites. And during the first Persian Gulf War, the new GPS was finally used by the military. Now scientists use the technology to track animals to better understand their movement and behavior. Parents who may be worried about their children can also use GPS technology to track them.

    Can you remember the first time you learned to ride a bike or drive a car? Learning these skills changed your life forever and opened up new horizons. Learning about computers can be like learning how to ride a bike or drive a car. Once you have invested the time to master the skills , you will never go back to the old days. The new technology is simply too convenient and too powerful.

    Technological developments through the years have enabled us to do more with less effort. We have continuously looked for better ways of doing things. Each invention and new development has allowed us to extend our capabilities. Today we see one of the most dramatic technologies ever developed—the computer. It extends the capabilities of our minds.

    Computers have saved organizations millions of dollars. Furthermore, these same computer systems have opened up new opportunities that would have gone undiscovered or neglected. The computer may multiply what we can do, and the return on investment is high. The growth of computer usage is surprising. On the other hand, the computer can do serious damage. Invasion of privacy(侵犯隐私), fraud(欺诈), and computer-related mistakes are just a few shocking examples.

    The computer is like a double-edged sword. It has the ability to cut us free from some activities, but it can also cut deep into profits, personal privacy, and our society in general. How it is used is not a function of technology. It is strictly a function of how people decide to use or misuse this new technology. The choice is yours, and only through a knowledge of computer systems will you be able to avoid the dangers while enjoying the many, many benefits of the computer age.

    Humans and many other mammals have unusually efficient internal temperature regulating systems that automatically maintain stable core body temperatures（核心体温）in cold winters and warm summers. In addition, people have developed cultural patterns and technologies that help them adjust to extremes of temperature and humidity（湿度）.

    In very cold climates, there is a constant danger of developing hypothermia（低体温）, which is a life threatening drop in core body temperature to below normal levels. The normal temperature for humans is about 37.0℃. However, differences in persons and even the time of day can cause it to be as much as 6℃ higher or lower in healthy individuals. It is also normal for core body temperature to be lower in elderly people. Hypothermia begins to occur when the core body temperature drops to 34.4℃. Below 29.4℃, the body cools more rapidly because its natural temperature regulating system usually fails. The rapid decline in core body temperature is likely to result in death. However, there have been rare cases in which people have been saved after their temperatures had dropped to 13.9—15.6℃. This happened in 1999 to a Swedish woman who was trapped under an ice sheet in freezing water for 80 minutes. She was found unconscious, not breathing, and her heart had stopped beating, yet she was eventually saved despite the fact that her temperature had dropped to 13.7℃.

    In extremely hot climates or as a result of uncontrollable infections, core body temperatures can rise to equally dangerous levels. This is hyperthermia. Life threatening hyperthermia typically starts in humans when their temperatures rise to 40.6—41.7℃. Only a few days at this extraordinarily high temperature level is likely to result in the worsening of internal organs and death.

    If English means endless new words, difficult grammar and sometimes strange pronunciation, you are wrong. Haven't you noticed that you have become smarter since you started to learn a language?

    According to a new study by a British university, learning a second language can lead to an increase in your brain power. Researchers found that learning other languages changes grey matter. This is the area of the brain which processes information. It is similar to the way that exercise builds muscles.

    The study also found the effect is greater when the younger people learn a second language. A team led by Dr. Andrea Mechelli, from University College London, took a group of Britons who only spoke English. They were compared with a group of "early bilinguals" who had learnt a second language before the age of five, as well as a number of later learners.

    Scans showed that grey matter density (密度) in the brain was greater in bilinguals than in people without a second language. But the longer a person waited before mastering a new language, the smaller the difference.

    "Our findings suggest that the structure of the brain is changed by the experience of learning a second language," said the scientists.

    It means that the change itself increases the ability to learn.

    Professor Dylan Vaughan Jones of the University of Wales, has researched the link between bilingualism and maths skills. "Having two languages gives you two windows on the world and makes the brain more flexible (灵活的)," he said. "You are actually going beyond language and have a better understanding of different ideas."

    The findings were matched in a study of native Italian speakers who had learned English as a second language between the ages of two and thirty-four. Reading, writing, and comprehension were all tested. The results showed that the younger they started to learn, the better. "Studying a language means you get an entrance to another world," explained the scientists.